PALAEONTOLOGICAL STUDY - Shodhgangashodhganga.inflibnet.ac.in/bitstream/10603/73160/13/13...Benthic...
Transcript of PALAEONTOLOGICAL STUDY - Shodhgangashodhganga.inflibnet.ac.in/bitstream/10603/73160/13/13...Benthic...
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CHAPTER 5
PALAEONTOLOGICAL STUDY
5. 1: Introduction
The three limestone members of the Shella Formation viz. Lakadong
Limestone, Umlatdoh Limestone and Prang Limestone are moderate to highly
fossiliferous.The fossil assemblage is represented by large and micro benthic
foraminiferas along with the calcareous algeae. Moreover, some ill-preserved
mollascan and coral shells are also seen mostly in shell partings. The fossil
assemblage large and micro foraminiferas and calcareous algeae are useful for
dating and interpreting their depositional environment.
Lakadong Limestone is characterizing by species of Ranikothalia,
Miscellanea, Glomalveolina, Discocyclina, microforms of Nummulites etc. Very few
Milioids viz Quinqueloqulina, Triloculina, Textularia are present in various
proportions. Moreover, this member also contains some important calcareous algae
fossils.
Miliods and Fasciolites represent the middle limestone unit. Amongst
Miliods and Alviolina is the most abundant genus, others are Quinqueloculina,
Triloculina and Textularia. A few Nummulitic genera are also present. Amongst
Fasciolites, Fasciolite elliptica is the main genus.
The uppermost member of the Shella Formation viz Prang Limestone
Member is characterizing by the abundance of larger and micro forams of
Nummulites, Discocyclina, Assilina, etc. Pellatispira is the only genus present in this
member. Moreover, some important algae fossils also characterize this member.
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5.2 Method of study
The method of study of fossils can be broadly classified as-(A) Field study.
(B) Laboratory study.
Field study:
For the purpose of field study, the following steps preceded -
(a) Preparation of base map 1:50,000 scale. (b) The samples collected from
the area under study include mainly hard, compact limestone, when collecting the
samples from the outcrop, care was taken that the rock is unweathered and
uncontaminated by recent vegetation or by hammer, chisels trowels and the hike.
Clear polythene sample bags with suitable closure device were used to keep the
collected samples. (c) The photographs are taken in the field.
Laboratory study:
The collected limestone sample is analyz for foraminifar and calcareous
algae study. Majority of the sample were yield rich foraminiferal assemblage and
calcareous algae study with more or less preservations.
Preparation of thin sections of fossils-
After the recovery of the individual tests from samples, thin sections were
made following the conventional methods. To study the internal structure of the
fossils, both axial and equatorial sections are prepared.
At first, the tests mounted on a slide by using Canda-balsam. For
preparation of equatorial sections, tests are mounted horizontally on the glass slide
and then grinded on a glass plate using finer abrasive powder (carborandum powder)
to reach the centre of the tests. Then again, the same tests are grinded by placing the
already grinded face as the glass slide to reach the centre of the tests. In axial section
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same principle is adopted except in the section the tests are mounted vertically on
the glass slide. Only one section can be prepared from one test. During this process,
a test is checked under microscope, time to time whether it is reaching the centre or
not. In the final stage 800 mesh, carborandum powder was used for grinding.
Usually a section of 0.3mm thick is best for study, cover slides is necessary in
preparing thin section for study.
5. 3: Microfauna: Foraminifera
The order foraminiferida or foraminifera as they are informally called
forams, the most important group of microfossils for two reasons: firstly, they are
abundant in rocks and there are numerous species; secondly, they provide valuable
information in the dating of strata and the reconstruction of sedimentary
environments.
Foraminifera have been utilised for biostratigraphy for many years, and they
have proven invaluable in palaeoenvironmental reconstructions most recently for
palaeoceanographical and palaeoclimatological purposes. For example,
palaeobathymetry where assemblage composition is used and palaeotemperature
where isotope analysis of foraminifer tests is a standard procedure. In terms of
biostratigraphy, foraminifera have become extremely useful, different forms have
shown evolutionary bursts at different periods and generally, if one form is not
available to be utilized for biostratigraphy another is. For example, preservation of
calcareous walled foraminifera is dependent on the depth of the water column and
Carbonate Compensation Depth (CCD) (the depth below which dissolution of
calcium carbonate exceeds the rate of its deposition), if calcareous walled
foraminifera are therefore not preserved agglutinated forms may be. The oldest
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rocks for which foraminifera have been biostratigraphically useful are Upper
Carboniferous to Permian strata, which have been zoned using the larger benthic
fusulinids. Planktic foraminifera have become increasingly important
biostratigraphic tools, especially as petroleum exploration has extended to offshore
environments of increasing depths. The first and last occurrence of distinctive
"marker species" from the Cretaceous to Recent (particularly during the Upper
Cretaceous) has allowed the development of a well-established fine scale
biozonation. Benthic foraminifera have been used for palaeobathymetry to
reconstruct palaeodepths. For studies of relatively recent deposits simple comparison
to the known depth distribution of modern extant species is used. For older material
changes in species diversity, planktic to benthic ratios, shell-type ratios and test
morphology have all been utilized. Variations in the water temperature inferred from
oxygen isotopes from the test calcite can be used to reconstruct palaeoceanographic
conditions by careful comparison of changes in oxygen isotope levels as seen in
benthic forms (for bottom waters) and planktic forms (for mid to upper waters).
Benthic foraminifera have been divided into, morphogroups based on the test shape
and these groups used to infer palaeo-habitats and substrates; infaunal species
tending to be elongate and streamlined in order to burrow into the substrate and
epifaunal species tending to be more globular with one relatively flatter side in order
to facilitate movement on top of the substrate.
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5.3.1: Classification of Benthic Foraminifera
Foraminiferas classified primarily on the composition and morphology of the
test. Three basic wall compositions are recognised, organic (protinaceous
mucopolysaccharide i.e. the allogromina), agglutinated and secreted calcium
carbonate (or more rarely silica). Agglutinated forms, i.e the Textulariina, may be
composed of randomly accumulated grains or grains selected on the basis of specific
gravity, shape or size; some forms arrange particular grains in specific parts of the
test. Secreted test foraminiferas again subdivided into three major groups,
microgranular (i.e. Fusulinina), porcelaneous (i.e. Miliolina) and hyaline (i.e.
Globigerinina). Microgranular walled forms (commonly found in the late
Palaeozoic) are composed of equidimensional subspherical grains of crystalline
calcite. Porcelaneous forms have a wall composed of thin inner and outer veneers
enclosing a thick middle layer of crystal laths; they are imperforate and made from
high magnesium calcite. The hyaline foraminifera add a new lamella to the entire
test each time a new chamber is formed; various types of lamellar wall structure
have been recognized, the wall is penetrated by fine pores and hence termed
perforate. A few "oddities" are also worth mentioning, the Suborder Spirillinina has
a test constructed of an optically single crystal of calcite, the Suborder
Silicoloculinina as the name suggests has a test composed of silica. Another group
(the Suborder Involutina) have a two chambered test composed of aragonite. The
Robertinina also have a test composed of aragonite and the Suborder Carterina is
believed to secrete spicules of calcite which are then weakly cemented together to
form the test (Table 5.1).
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Table 5.1: Classification of Foraminifera (after Loeblich and Tappan, 1988)
Phylum - Sarcomastgophora,
Subphylum - Sarcodina,
Superclass - Rhizopoda,
Class - Granuloreticulosea,
Order - Foraminiferida, Eichwald, 1830
Suborder ALLOGROMINA, Loeblich and Tappan, 1961
Suborder FUSULINIINA, Wedekind, 1937
Suborder TEXTULARINIINA, Delage and He’rouard, 1896
Suborder INVOLUTININA, Hohenegger and Piller, 1977
Suborder CARTERRINA, Loeblich and Tappan, 1981
Suborder MILIOLINA, Delage and He’rouard, 1896
Suborder ROBERTININA, Loeblich and Tappan, 1984
Suborder SPIRILININA, Hohenegger and Piller, 1975
Suborder SILICOLOCULININA, Resig, Lowenstam, Echols, and Weiner, 1980
Suborder LAGENINA, Delage and He’rouard, 1896
Suborder GLOBIGERININA, Delage and He’rouard, 1896
Suborder ROTALIINA, Delage and He’rouard, 1896
The species of the familys of benthic foraminifera is available in the study area are
as follows-
Family Nummulitidae de Blainville, 1827
Family Miscellaneidae, Sigal, 1952
Family Textulariidae, Ehrenberg, 1838
Family Miliolidea, Hauerinidae Schwager, 1876
Family Hauerinidae Schwager, 1876
Family Alveolinidea Ehrenberg, 1839
Family Nummulitidae, Galloway, 1928
Family Discocyclinidae Galloway, 1928
Family Calcarinidae D'Orbigny, 1826
Family Rotalidae Ehrenberg, 1839
Family Soritidae Ehrenberg 1839
Family Fabulariidae Ehrenberg, 1839
Family Eponididae Hofker, 1951
Family Lepidorbitoididae Vaughan, 1933
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5.3.2: Distribution of foraminifera
The calcareous sediments of Shella Formation are rich in benthonic
foraminiferal assemblages. The assemblages contain Cenozoic foraminifera ranging
from Paleocene to Eocene. Both larger and micro-foraminifers were encountered
from the study area.
The Lakadong Limestone Member of the Sylhet Formation yielded a number
of foraminiferal assemblages. The typical Late Paleocene (Montian) foraminifera
Miscellanea miscella found to occur in this limestone member. The member is with
few Miliolids, which contain Quinqueloculina, Spiroloculina, Triloculina and
Textularia. Moreover, it is also rich in calcareous algae. Among other foraminifers,
Lokhartia haimei, Glomalveolina primaeva, Ranikothalia nuttalli etc. also found to
be present in this limestone member. These foraminiferal assemblages are yielded
by the exposed sequences in the study area.
The Umlatdoh Limestone Member is represented by typical early to middle
Eocene (Ypresian) fauna. It consists of only Fasciolites elliptica from bottom to top
of the member. Some forms of Miliolids are also found to occur in the member.
The uppermost member of the Sylhet Limestone Formation viz. the Prang
Limestone Member, is rich in middle Eocene (Lutetian) foraminiferal microfauna.
Among Discocyclines, Discocyclina pygmaea, and Discocylina omphalus found to
occur. The member has yielded a number of Nummulites like Nummulites obtusus,
Nummulites acutus Sowerby, Nummulites beaumonti D’Archiac and Haime and
Nummulites pengaronensis Verbeek etc. Moreover the member is also consisting of
Pellatispira madaraszi, Textularia sp. etc.
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Table 5.2: showing specise name availability (Index: ‘a’ - available)
Sl.No. and Specise name Lakadong
Limestone
Umlatdoh
Limestone
Prang
Limestone
1. Nummulites pengaronensis Verbeek, 1871 a
2. Nummulites acutus Sowerby, 1840 a
3. Nummulites millecaput Boubee, 1832 a
4. Nummulites globules Leymerie, 1846 a
5. Nummulites beaumonti d’Archiac and Haime 1853 a
6. Nummulites perforatus (de Montfort), Sengupta, 1965 a a
7. Nummulites pratti d'Archiac and Haime, 1853 a a
8. Nummulites mamillatus (Fichtel and Moll) a a
9. Nummulites preaturicus Schaub, 1962 a
10. Nummulites obtusus Sowerby, 1840 a
11. Ranikothalia nuttalli (Davies) Nagappa, 1959 a
12. Ranikothalia sindensis (Davies) Caudri, 1944 a
13. Ranikothalia sp. a
14. Miscellanea sp. a
15. Miscellanea juliettae Leppig, 1988 a
16. Miscellanea yvettae Leppig, 1988 a
17. Glomalveolina primaevea Reichel, 1937 a
18. Glomalveolina primaevea Hottinger, 1962 a
19. Glomalveolina levis (Hottinger, 1960) a
20. Textularia sagittula Defrance, 1824 a
21. Textularia barretti Jones and Parker, 1871 a
22. Textularia biserial, de Blainville, 1824 a
23. Quinoqueloculina seminulum Linne, 1958 a
24. Quinoqueloculina sp. a
25. Triloculina sp. a
26. Triloculina sp. a
27. Triloculina trigonula (Lamarck, 1804) a
28. Idalina sinjarica Grimsdale, 1952 a
29. Alveolina oblonga d’Orbigny, 1826 a
30. Alveolina elliptica Sowerby, 1840 a
31. Alveolina dachelansis Schwager, 1883 a
32. Alveolina munieri Hottinger, 1960 a
33. Alveolina ovulum Stachein Schwager, 1883 a
34. Alveolina globosa Leymerie, 1846 a
35. Alveolina schwageri Checchia-Rispoli a
36. Alveolina solida Hottinger, 1960 a
37. Alveolina (Glomalveolina) levis (Hottinger, 1960) a
38. Alveolina elliptica (Sowerby) a
39. Alveolina daniensis Drobne, 1977 a
40. Alveolina ellipsoidalis Schwager, 1883 a
41. Alveolina cf. elliptica (Sowerby), a
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42. Alveolina decipiens Schwager, a
43. Alveolina cf. dainellii Hottinger, 1960 a
44. Alveolina aragonensis Hottinger, 1960 a
45. Alveolina nuttalli (Davies, 1940) a
46. Alveolina D'Orbigny, 1826, Alveolina sp. a
47. Alveolina D'Orbigny, 1826, Alveolina sp. a
48. Fasciolites elliptica Sowerby; Nuttal, 1925 a
49. Discocyclina ranikotensis Davies a
50. Discocyclina pygmae Henrici, 1934 a
51. Discocyclina archiaci Schlumberger a
52. Discocyclina javana (Verveek) 1892 a
53. Discocyclina, Gumbel, 1970, Discocyclina sp. a
54. Genus Discocyclina, Gumbel, 1970, Discocyclina sp. a
55. Discocyclina, Gumbel, 1868, Discocyclina sp. a
56. Discocyclina, Gumbel, 1868, Discocyclina sp. a
57. Pellatispira inflata Umbgrove, 1928; a
58. Pellatispira madaraszi Hantken, 1941 a
59. Pellatispira orbitoidea (Provale) a
60. Genus - Pellatispira, Boussac, 1906 a
61. Pellatispira orbitoidea (Provale), Umbgrove, 1928 a
62. Operculina patalensis Davies & Pinfold, 1937 a
63. Operculina, d’Ordigny, 1826, Operculina sp. a
64. Rotalites trochidiformis Lamarck, 1804 a
65. Lockhartia haimei Devies, Davies and Pinfold, 1937 a
66. Orbitolites complanatus Lamarck, 1801 a
67. Assilina spira Corrugate a
68. Assilina laminosa Gill, 1953 a
69. Biloculinites paleocenica Rahagi, 1983 a
70. Biloculinites Rahaghi, 1983, Biloculina sp. a
71. Biloculina murrhyna Schwager, 1866 a
72. Eponides de Montfort, 1808, Eponides sp. a
73. Orbitosiphon punjabensis (Davies) Tan, 1939 a
Checklist of the foraminifera
The recorded foraminiferal assemblage from the study area comprises 34
taxa belonging to 20 genera and 14 families and all have been recognised upto
specific level. The checklist of the taxa is as follows-
(Nummulitidae de Blainville, 1827; Miscellaneidae, Sigal, 1952;
Textulariidae Ehrenberg, 1838; Miliolidea (Hauerinidae Schwager, 1876);
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Hauerinidae Schwager, 1876; Textulariidae Ehrenberg, 1838; Alveolinidea
Ehrenberg, 1839; Nummulitidae, Galloway, 1928; Discocyclinidae Galloway, 1928;
Calcarinidae; Rotalidae Ehrenberg, 1839; Rotaliidae; Soritidae Ehrenberg 1839;
Fabulariidae Ehrenberg, 1839; Eponididae Hofker, 1951; Lepidorbitoididae
Vaughan, 1933).
1. Nummulites pengaronensis Verbeek, 1871
2. Nummulites acutus Sowerby, 1840
3. Nummulites millecaput Boubee, 1832
4. Nummulites globules Leymerie, 1846
5. Nummulites beaumonti d’Archiac and Haime 1853
6. Nummulites perforatus (de Montfort), Sengupta, 1965
7. Nummulites pratti d'Archiac and Haime, 1853
8. Nummulites mamillatus (Fichtel and Moll)
9. Nummulites preaturicus Schaub, 1962
10. Nummulites obtusus Sowerby, 1840
11. Ranikothalia nuttalli (Davies), Nagappa, 1959
12. Ranikothalia sindensis (Davies) Caudri, 1944
13. Ranikothalia sp.
14. Miscellanea sp.
15. Miscellanea juliettae Leppig, 1988
16. Miscellanea yvettae Leppig, 1988
17. Glomalveolina primaevea Reichel, 1937
18. Glomalveolina primaevea Hottinger, 1962
19. Glomalveolina levis (Hottinger, 1960)
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20. Textularia sagittula Defrance, 1824
21. Textularia barrette Jones and Parker, 1871
22. Textularia biserial de Blainville, 1824
23. Quinoqueloculina seminulum Linne, 1958
24. Quinoqueloculina sp.
25. Triloculina sp.
26. Triloculina sp.
27. Triloculina trigonula (Lamarck, 1804), d’ Orbigny, 1826
28. Idalina sinjarica Grimsdale, 1952
29. Alveolina oblonga d’Orbigny, 1826
30. Alveolina elliptica (Sowerby, 1840)
31. Alveolina dachelansis Schwager, 1883
32. Alveolina munieri Hottinger, 1960
33. Alveolina ovulum Stachein Schwager, 1883
34. Alveolina globosa Leymerie, 1846
35. Alveolina schwageri Checchia-Rispoli
36. Alveolina solida Hottinger, 1960
37. Alveolina (Glomalveolina) levis (Hottinger, 1960)
38. Alveolina elliptica (Sowerby)
39. Alveolina daniensis Drobne, 1977
40. Alveolina ellipsoidalis Schwager, 1883
41. Alveolina cf. elliptica (Sowerby),
42. Alveolina decipiens Schwager,
43. Alveolina cf. dainellii Hottinger, 1960
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44. Alveolina aragonensis Hottinger, 1960
45. Alveolina nuttalli (Davies, 1940)
46. Alveolina D'Orbigny, 1826, Alveolina sp.
47. Alveolina D'Orbigny, 1826, Alveolina sp.
48. Fasciolites elliptica Sowerby; Nuttal, 1925
49. Discocyclina ranikotensis Davies
50. Discocyclina pygmae Henrici, 1934
51. Discocyclina archiaci Schlumberger
52. Discocyclina javana (Verveek) 1892
53. Discocyclina, Gumbel, 1970, Discocyclina sp.
54. Discocyclina, Gumbel, 1970, Discocyclina sp.
55. Discocyclina, Gumbel, 1868, Discocyclina sp.
56. Discocyclina, Gumbel, 1868, Discocyclina sp.
57. Pellatispira inflata Umbgrove, 1928
58. Pellatispira madaraszi Hantken, 1941
59. Pellatispira orbitoidea (Provale)
60. Pellatispira, Boussac, 1906, Pellatispira sp.
61. Pellatispira orbitoidea (Provale), Umbgrove, 1928
62. Operculina patalensis Davies and Pinfold, 1937
63. Operculina, d’Ordigny, 1826, Operculina sp.
64. Rotalites trochidiformis Lamarck, 1804
65. Lockhartia haimei Devies, Davies and Pinfold, 1937
66. Orbitolites complanatus Lamarck, 1801
67. Assilina spira Corrugate
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68. Assilina laminosa Gill, 1953
69. Biloculinites paleocenica Rahagi, 1983
70. Biloculinites, Rahaghi, 1983, Biloculina sp.
71. Biloculina murrhyna Schwager, 1866
72. Eponides de Montfort, 1808, Eponides sp.
73. Orbitosiphon punjabensis (Davies) Tan, 1939
5.3.3: Age range of diagnostic species
Foraminfers are widely used in stratigraphy as they were widely distributed
all over the world. Though as a whole, they have long geological distribution, some
of the genera and species have short geological distribution. That is why; they are
now useful for age determination and correlation purposes as index fossils.
Foraminifers are in many respects ideal zonal indices for marine rocks due to
their wide distribution and extremely diverse type. Many also have an intricate
morphology in which evolutionary changes can be readily traced. Planktonic
foraminifers provide the basis of important schemes for intercontinental correlation
of Mesozoic and Cenozoic rocks. Moreover, they are now widely used in Deep Sea
Stratigraphy. Benthic foraminifers tend to be more restricted in distribution but
useful scheme for local correlation.
Many workers have outlined the value of foraminifers as indicator of depth
of deposition, comparison in most of the cases being made with the depth ranges of
recent genera and species. Evidence for vertical movements in young oceanic crust
has been computed from such studies in Cenozoic rocks. Benthic depth related
assemblages are determined for Tertiary sediments. Moreover, depth related
assemblages are also recognized in Cretaceous sediments. Moreover, it is recorded
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that higher diverse assemblages are gradually found in deeper waters than in
shallower waters.
Environmental interpretations that use fossil foraminifers are found mainly
on comparisons with the numerous studies of recent ecology. Moreover,
palaeogeography, palaeosalinity and palaeotemperture are also determined with the
help of different foraminifera after studying the present forms. The narrow
temperature ranges of planktonic species have become useful tools for studying
palaeoclimatology.
For the varied scope of applications, foraminifers are ideal fossils used in
petroleum and marine coal deposits because majority of the oil and coal deposits
associated with marine rocks which bear abundant foraminifers. Foraminifers are of
considerable values in oil exploration and oil field development. They are also
useful for determination of ancient shore line, depth of basin, fluctuation of sea
level, determination of palaeotemperature and palaeosalinity etc. Besides these they
are also helpful to determine the depositional condition of the calcareous sediments.
5.3.4: Systemetic descreption of some diagnostic species
The three limestone members of the Shella Formation viz Lakadong
Limestone, Umlatdoh Limestone and Prang Limestone are moderate to highly
fossiliferous. The fossil assemblages are represented by larger and smaller (micro)
mostly benthic foraminiferas along with the calcereous algeae. Some of the
diagnostic species and their systemetic descreption are as follows-
1. Nummulites sp.
Phylum - Protozoa Von Seibold, 1845
Sub-phylum - Sarcodina, Shamards, 1871
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Class -Reticularia Lankester, 1871
Sub-class - Granuloreticularia Saedclur, 1934
Order - Foraminiferida Eichwald, 1830
Family - Nummulitidae de Blainville, 1827
Genus - Nummulites Lamarck, 1801
Distinguishing characteristics: The Megalospheric generation has an elongated
ovoid test with maximum length of 0.70mm and maximum width of 0.50mm. The
chambers are arranged bilocularly throughout ontogeny. The megalosphere and
aperture have not been observed.
Remarks: Nummulites are a large and important variety of single-celled organisms,
or 'protists'. These otherwise amoeba-like creatures build themselves elaborate shells
of calcium carbonate. These shells increase in size in a predictable way as the
creataceous age, and, being made of mineral, the shells are preserved readily as
fossils.
Type species - Nummulites pengaronensis Verbeek, 1871
Section: 7, Figure: 5.01
Nummulites pengaronensis Verbeek, 1871, p.3-6, pl.1, figs.1a-k
Nummulites pengaronensis (Vrbeek, 1871), Nagappa, 1959, pl.5, fig.3, pl. 9, figs.
Pl. 10, figs. 3-5; Samanta, 1968, p. 676-680, pl. 128, figs. 1-10; Samanta, 1988, pl.5,
fig.1; Saraswati et.al.2000, pl.4, figs. 9-16; Govindan, 2003, pl.3 figs 1a-b.
Remarks: The specimens are referable to Nummulites pengaronensis Verbeek
(1871).
Horizon: Prang Limestone, Shella formation, Jaiantia Group.
Locality: From near Shella Bazar, East khasi Hills District, Meghalaya, India
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Stratigraphic range (Age): Middle Eocene to Upper Eocene
Genus - Nummulites, Lamarck, 1801
Type species - Nummulites acutus Sowerby, 1840
Nummulites acutus Sowerby; Nuttal, 1926, Geol, Surv. Rec. vol. 59, pp. 115-164, pl.
2, figs. 1-4
Section: 4, Figure: 5.02 and 5.03
Distinguishing characteristics: Megalospheric, forms are abundantly recorded from
the study area. The megalospheric forms are highly biconvex with centrally raised
mamelon which is covered by strong pustules. The margins of the shells are very
sharp. The initial chambers of the tests are large and nearly circular. The number of
whorls is 5-7 and the coiling is + regular in equatorial sections. Septa are thin.The
diameter of the tests varies from 2.1mm to 3.5mm and the thickness from 1.4mm to
2.1mm. However, a maximum diameter of 4.4mm and a maximum thickness of
2.6mm are recorded from the study area.
Remarks: This species is reported from Kutch and Cambay basin (Pandey, 1972)
and also from Jaisalmer basin (Singh, 1983).
Horizon: Prang Limestone and Umlatdoh Limestone, Shella formation, Jaintia
Group.
Locality: Shella and Ishamati area, East khasi Hills District, Meghalaya, India
Stratigraphic range (Age): Upper Eocene
Genus - Nummulites, Lamarck, 1801
Type species - Nummulites millecaput Boubee, 1832
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Section: 4, Figure: 5.03
Distinguishing characteristics: The megalospheric forms are highly biconvex with
centrally raised mamelon, which is covered by strong pustules. The margins of the
shells are very sharp. The initial chambers of the tests are large and nearly circular.
The values for the thickness of the shell, the diameter of the initial chamber, and the
ratio of the diameter of the third whorl to the diameter of the initial chamber are
normally distributed around the mean. The thickness of the spiral layer increases to
the third whorl, then decreases. The diameter of the initial chamber correlates with
the diameter rather than the thickness of the shell.
Remarks: Foraminifera are generally microscopic, but Nummulites millecaput,
which lived in the Eocene epoch around 50 million years ago, during the warmest
climatic episode since before the demise of the dinosaurs, grew to 160 mm in
diameter. After this acme, nummulites declined in size and diversity, and their living
relatives seldom exceed 2 mm in size or live longer than a year or two. These are
disc-shaped, single-celled organisms called nummulites, some of which were as big
as coasters and could have lived for more than a century - certainly the biggest, and
arguably the longest-lived, of all known single-celled creatures (Henry, 1999)
Horizon: Prang Limestone and Umlatdoh Limestone, Shella formation, Jaintia
Group.
Locality: Shella and Ishamati area, East khasi Hills District, Meghalaya, India
Stratigraphic range (Age): Middle Eocene to Upper Eocene.
Genus - Nummulites, Lamarck, 1801
Type species - Nummulites globules Leymerie, 1846
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Nummulites globulus Leymerie, 1846; p.359, pl. XIII, figs. 14a, 14 d
Section: 4, Figure: 5.04 and 5.05
Distinguishing characteristics: Megalospheric, forms are highly biconvex with
centrally raised mamelon, which is covered by strong pustules. The margins of the
shells are very sharp. The initial chambers of the tests are large and nearly circular.
The number of whorls is 4-5 and the coiling is + regular in equatorial sections. Septa
are thin.The diameter of the tests varies from 2.0mm to 3.5mm and the thickness
from 1.5 mm to 2.0 mm.
Remarks: This genus is reported from Upper Eocene rocks of Kutch and Cambay
basin (Pandey, 1972) and from Jaisalmer basin (Singh, 1983).
Horizon: Umlatdoh Limestone, Shella formation, Jaintia Group.
Locality: Shella and Ishamati area, East khasi Hills District, Meghalaya, India
Stratigraphic range (Age): Upper Eocene
Genus - Nummulites, Lamarck, 1801
Type species - Nummulites beaumonti d’Archiac and Haime 1853
Nummulites beaumonti d’Archiac and Haime, 1853, p.133, pl.8 figs. la-e 2, 3
Nummulites beaumonti (d’Archiac and Haime), Davies, 1940, p 206-209,pl.ix,
figs.1-9, Nagappa, 1959,pl.5,fig.2,pl.8,figs.15,17, pl.9, figs.12; Sengupta, 1965,
pl.15,figs.1,2 &5, pl.16, figs.3,7,9,10, pl.17,figs.1,5,7,12; Govindan, 2003,
pl.2,figs.2a-b.
Section: 4, Figure: 5.06
Distinguishing characteristics: Test lenticular to biconical, the marginal cord is
distinct and pillars increase in thickness at the polar region forming axial plug.
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Remarks: The morphological character of the species is more akin to Nummulites
beaumonti. Sengupta, 1965 treated this species as synonemous to Nummulites
pengaronensis. However, Saraswati et. al. (2000) suggested that Nummulites
pengaronensis is a morphologically distinct species.
Horizon: Umlatdoh Limestone, Shella formation, Jaintia Group.
Locality: Shella and Ishamati area, East khasi Hills District, Meghalaya, India
Stratigraphic range (Age): Middle Eocene to Upper Eocene
Genus - Nummulites, Lamarck, 1801
Type species - Nummulites perforatus (de Montfort), Sengupta, 1965,
Nummulites perforatus (de Montfort),
Sengupta, 1965, pl.16, figs.1, 2 and 11, pl.17, figs.3, 9, 10, 13; Samanta, 1981, ap.
818, pl.16, figs.1-2; Govindan, 2003, pl.3, figs. 2a-b.
Section: 4 and 5, Figure: 5.07 and 5.12
Distinguishing characteristics: Test lenticular or flat disc shaped, often saddle-
shaped or with undulating border, edge sharp. Surface with strongly curved or
meandriform raised lines, joining in one or more points, often not very clear or
lacking.
Remarks: The morphological character of the species is more akin to Nummulites
perforatus. Sengupta (1965) treated this species as synonemous to Nummulites
perforatus. However, Samanta, 1981 suggested that Nummulites perforatus is a
morphologically distinct species with Nummulites perforatus of de Montfort.
Horizon: Umlatdoh Limestone and Prang Limestone, Shella formation, Jaintia
Group.
Locality: Shella and Ishamati area, East khasi Hills District, Meghalaya, India
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Stratigraphic range (Age): Middle Eocene to Upper Eocene
Genus Nummulites, Lamarck, 1801
Type species Nummulites pratti d'Archiac and Haime, 1853;
Nummulites pratti d'Archiac and Haime, 1853;
Nummulites pratti (d'Archiac and Haime) Schaub (1981), Pl. 65, Figs. 32-53.
Section: 4 and 5, Figure: 5.08
Distinguishing characteristics: Test lenticular to biconical. The marginal cord is
distinct and pillars increase in thickness at the polar region forming axial plug, edge
sharp, surface with strongly curved or meandriform raised lines.
Remarks: Schaub (1981), several specimens to this species that displayed a large
proloculus (0.5 mm) and a growth rate similar to that of N. pratti. The specimen
illustrated in Figure 5.07, is a characteristic axial section of N. pratti.
Horizon: Umlatdoh Limestone and Prang Limestone, Shella formation, Jaintia
Group.
Locality: Shella and Ishamati area, East khasi Hills District, Meghalaya, India
Stratigraphic range (Age): Middle Eocene to Upper Eocene
Genus - Nummulites, Lamarck, 1801
Type species - Nummulites mamillatus (Fichtel and Moll);
Nummulites mamillatus Fichtel and Moll, 1798
Nummulites mammillatus (Fichtel and Moll), Nuttal, 1925, p. 445, pl. 27, figs. 1-3.
Section: 4 and 5, Figure: 5.09
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Distinguishing characteristics: Test lenticular to biconical. The marginal cord is
distinct, thick wall, narrowly spaced chambers and the presence of umbonal pillars
as seen in the vertical view. The specimen is strongly biconvex.
Remarks: This species is very common and abundant in Middle Eocene Kohat
Formation, Shekhan Nala, Kohat Basin, and Northern Pakistan. It is characterize by
having a biconvex shell with thick umbilical pillars in the middle part. Marginal
cord is present, but comparatively thin as compared to the other species of
Nummulites (Mirza, et. al. 2005).
Horizon: Umlatdoh Limestone and Prang Limestone, Shella formation, Jaintia
Group.
Locality: Shella and Ishamati area, East khasi Hills District, Meghalaya, India
Stratigraphic range (Age): Middle Eocene to Upper Eocene
Genus - Nummulites, Lamarck, 1801
Type species - Nummulites preaturicus Schaub, 1962
Nummulites preaturicus Schaub, 1962, A Form. P1. 28, figs 6-7
Section: 5 and 6, Figure: 5.10
Distinguishing characteristics: Test lenticular or flat disc shaped or with undulating
border, edge sharp. Surface with strongly curved or meandriform raised lines,
joining in one or more points, often not very clear or lacking.
Remarks: The morphological character of the species is more akin to N. preaturicus.
Schaub (1962) treated this species as synonemous to Nummulites preaturicus.
Horizon: Prang Limestone, Shella formation, Jaintia Group.
Locality: Shella and Ishamati area, East khasi Hills District, Meghalaya, India
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Stratigraphic range (Age): Middle Eocene to Upper Eocene
Genus - Nummulites, Lamarck, 1801
Type species - Nummulites obtusus Sowerby, 1840
Nummulites obtusus Sowerby, 1840, p.329, pl. 24, fig. 14
Nummulites obtusus (Sowerby), 1840; Schaub, 1981, p 106; table 3, fig. g ;
Samanta, 1981a, p 804; pl 113, figs. 3-5; pl 114, pl 115; Samanta et.al., 1990, p 37-
38; pl 8, figs. 1-4; pl 9, figs.1, 3-10, pl 10, figs. 19-28, pl. 11, figs. 6-9; Racey,
1995, p. 55-56, pl. 3, figs. 8-10
Section: 5 and 6, Figure: 5.11
Distinguishing characteristics: Megalospheric form, test inflated, lenticular or flat
disc shaped, with a broadly rounded mergin, septal filaments sinuous to
meandriform, fine granuls attached to some septal filament; edge sharp.
Remarks: The morphological character of the species is more akin to N. obtusus
(Sowerby, 1840).Sengupta (1965) treated this species as synonemous to N.
perforatus from the Harudi Formation. Samanta (1981a) has shown that although
this species has been reported from different parts of Tethyan regions, the only
verifiable records from Kutch in India and the adjoining Sind areas of Pakistan.
Racey (1995) reported it from Oman.
Horizon: Prang Limestone, Shella formation, Jaintia Group.
Locality: Shella and Ishamati area, East khasi Hills District, Meghalaya, India
Stratigraphic range (Age): Middle Eocene to Upper Eocene
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2. Ranikothalia sp.
Order - Foraminiferida Eichwald, 1830
Suborder - Rotalina Delage and Herourd, 1896
Superfamily - Nummulitacea de Blainville, 1827
Family - Nummulitidae de Blainville, 1827
Genus - Ranikothalia Caudri, 1944
Type Species - Ranikothalia nuttalli (Davies) Nagappa, 1959
Ranikothalia nuttalli (Davies) Nagappa, 1959, pl.3, fig.3;
Ranikothalia nuttalli (Davies) Samanta, 1988, pl.1, fig.1-2, pl.8, figs. 5 & 11, 12.
Section: 1, Figure: 5.19
Distinguishing characteristics: The test elongated, lenticular with central boss.
Megalospheric form with bilocular embryo 9.4-6.0mm in diameter. Chambers have
very long prolongations.
Remarks: The diagnostic characters are more akin to Ranikothalia nuttalli Davies,
which is a very common form present in the Paleocene outcrops of India.
Horizon: Lakadong Limestone, Shella formation, Jaintia Group.
Locality: Near Mawlong, East khasi Hills District, Meghalaya, India
Stratigraphic range (Age): Middle Paleocene to Upper Paleocene
Type Species - Ranikothalia sindensis (Davies) Caudri, 1944
Operculina sindensis Davies, 1927, p. 274, pl. 19, figs. 10-13.
Nummulites sindensis (Davies), 1937, Davies and Pinfold, p. 21, pl. 4, fig. 21.
Nummulitoides sindensis (Davies), 1967, Barut, Bouroullec and Villatte, p. 384, pl.
1-3.
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Ranikothalia bermudezi (Palmer), 1969, Butterlin and Monod, p. 595, pl. 2, fig. 1-2.
Ranikothalia sindensis (Davies), 1969, Butterlin and Monod, pl. 2, fig. 4.
Ranikothalia sindensis (Davies), 1977, Hottinger, p. 50, pl. 16, figs. 1-5.
Ranikothalia sindensis (Davies), 1983, Sirel, Gunduz and Acar, p. 151, pl. 3, figs. 8-
10.
Ranikothalia sindensis (Davies), 1991, Butt, p. 77, pls. 1-4.
Section: 1, Figure: 5.20 and 5.21
Distinguishing characteristics: The test compressed and involute. The axial section
showing very long, thin alar prolongations but continue to umbilicus. Wall
calcareous and structure is not coarsely perforate except at the marginal cord.
Marginal cords thick, swollen and coarsely perforat. The length of the test is 6.1 mm
and breath measure is 0.98 mm to 0.32 mm. The umbilical portions have a thickness
of 0.66 mm. Inner length of the initial chamber 0.30 mm and with 0.10 mm.
Remarks: The majority of specimens of Ranikothalia sindensis are flattened and
almost identical to the figured specimens of Butt (1991) and Sirel (1998). The base
of the Ranikothalia sindensis Zone corresponds to the first stratigraphic appearance
of Idalina sinjarica Grimsdale, Fallotella alavensis Mangin in the commonly
occurring Palaeocene assemblage of Miscellanea miscella (D’Archiac and Haime),
and Haymanella paleocenica Sirel. The succeeding Zone is marked with the entry of
Assilina laminose Gill, Discocyclina dispansa Sowerby and associated with
Opertorbitolites douvillei (Nuttall), Alveolina pasticillata Schwager in Early Eocene
(Babazadeh, 2011).
Horizon: Lakadong Limestone, Shella formation, Jaintia Group.
Locality: Near Mawlong, East khasi Hills District, Meghalaya, India
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Stratigraphic range (Age): Middle Paleocene to Upper Paleocene
Family - Nummulitidae de Blainville, 1827
Genus - Ranikothalia Caudri, 1944
Ranikothalia sp.
Section: 1, Figure: 5.22
Distinguishing characteristics: The test compressed and involute. The axial section
showing long, thin alar prolongations (comparatively thicker than Ranikothalia
sindensis), but continue to umbilicus. Wall calcareous and structure is not coarsely
perforate except at the marginal cord. Marginal cords thick and perforate. Proloculus
not seen. Length of the specimen is 3.1 mm and width 0.70 mm.
Remarks: The majority of specimens of Ranikothalia sp. are flattened and almost
identical to the figured specimens of Butt (1991) and Sirel (1998). The genus
Ranikothalia Caudri, 1944 was recorded from Late Paleocene rocks and showing a
similar stratigraphic distribution in Middle East. It is reported for the first time from
Lower Eocene platform limestones in eastern Iran (Babazadeh, 2011).
Horizon: Lakadong Limestone, Shella formation, Jaintia Group.
Locality: Near Mawlong, East khasi Hills District, Meghalaya, India
Stratigraphic range (Age): Late Paleocene to Early Eocene
Superfamily - Nummulitacea de Blainville, 1827
Family - Miscellaneidae, Sigal, 1952
Genus - Miscellanea, Pfender, 1934
Type species - Miscellanea sp.
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Miscellanea miscella D’Archiac and Haime, 1853
Nummulites miscella D’Archiac and Haime, 1853, 1853, p. 345, Pl. 35, figs. 4a-c.
Siderolites miscella (D’Archiac and Haime) Douville, 1916, p. 38, Pl. 15.
Miscellanea miscella (d’Archiac and Haime), Pefender, 1935, p.231, pl.11, figs.6, 7,
pl.13, figs. 2-4; Davies and Pinfold, 1937, p.43, pl.4, figs.1-3, 7-8.
Miscellanea miscella (d’Archiac and Haime), Nagappa, 1959, p.3, pl.4, figs.1;
Samanta, 1988, pl.1, figs.2, pl. 8.figs.6, 8, 9 and 13; Jauhri, 1998, pl.1, figs.2-3, pl.2,
figs.9,11; Govindan, 2003.pl.4, figs.16a-b.
Section: 1, Figure: 5.13 and 5.14
Distinguishing characteristics: The form is globular and lenticular in shape. Both
microspheric and megalospheric forms are much more abundant and they are
elongated. Marginal chord is not observed in the forms. The coiling is involute. The
spire interval enlarges slightly and gradually throughout the coiling. The shapes of
the chambers are irregular, mostly their tops are rounded and their heights are
always more than their widths. The numbers of whorls are usually three but
sometimes an incomplete outer whorl is also observed.
Remarks: The form is recorded from the Late Paleocene of Ranikot, Punjab Salt
Range and Lakadong Limestone of Khasi and Jaintia Hills, Meghalaya.
Horizon: Lakadong Limestone, Shella formation, Jaintia Group.
Locality: Near Mawlong, East khasi Hills District, Meghalaya, India
Stratigraphic range (Age): Late Paleocene.
Type species - Miscellanea juliettae Leppig, 1988
Section: 1, Figure: 5.15 and 5.16
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Distinguishing characteristics: both megalospheric (A-form) and microspheric (B-
form) forms represent this species. The megalospheric equatorial section observed in
thin sections of the sample shows invaginated body whorl. Diameter of the test is
1.20 mm and size of the proloculus is 0.16 mm. Number of body whorl is 2. Sixteen
and eleven chambers are observed in the last whorl and first whorl respectively.The
megalospheric axial sections are observed in thin sections of the sample. The form is
strongly biconvex and involute. Strong ornamental pillars are confined to the
umbilical area. Diameter of the proloculus is 0.10 mm. Length, breath of the test is
1.40 mm, and 0.90 mm respectively.The microspheric equatorial sections are
observed in the thin sections of the sample. Diameter of the test is 1.50 mm and 3.5
numbers of whorls are observed.The microspheric axial section observed in thin
sections of the sample are characterised by strongly invaginated peripheral margin.
The length and breath measured in the form is 1.70 mm and 0.90 mm respectively.
The ornamental pillars are confined to the umbilical area.
Remarks: The form is recorded from the Late Paleocene of Ranikot, Punjab Salt
Range and Lakadong Limestone of Khasi and Jaintia Hills, Meghalaya.
Horizon: Lakadong Limestone, Shella formation, Jaintia Group.
Locality: Near Mawlong, East khasi Hills District, Meghalaya, India
Stratigraphic range (Age): Late Paleocene.
Type species Miscellanea yvettae Leppig, 1988
Section: 1, Figure: 5.17 and 5.18
Distinguishing characteristics: The megalospheric equatorial sections of the
specimens observed in the sample shows in vaginate peripheral margin. The
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diameter of the test is 1.1 mm and proloculus is 0.15 mm. Length of the test is 1.40
mm and breath of the test is 0.90 mm. Microspheric axial section of the specimen is
observed in the thin sections of the sample, the length of the test is 1.50 mm and
breath is 0.70 mm. Size of the proloculus is 0.03 mm.
Remarks: Miscellanea yvettae in Lakadong Limestone is represented by both
megalospheric (A-form) and microspheric (B-form) specimen. The specimen is
occurring less commonly then the other two specimens of Miscellanea viz. M.
juliettae and M. miscella.
Horizon: Lakadong Limestone, Shella formation, Jaintia Group.
Locality: Near Mawlong, East khasi Hills District, Meghalaya, India.
Stratigraphic range (Age): Late Paleocene.
4. Glomalveolina sp.
Order - Foraminiferida Eichwald, 1830
Family - Alveolinidae Ehrenberg, 1839
Genus - Glomalveolina Reichel, 1937
Type Species - Glomalveolina primaevea Reichel, 1937
Glomalveolina primaeva (Reichel, 1936); Pl. 5, fig. 5; Pl. 7, Figs. 7b, 8a–b
Section: 2, Figure: 5.82
Glomalveolina primaevea Hottinger, 1962
Section: 2, Figure: 5.83
Distinguishing characteristics: Test circular (Fig 5.82 and Fig 5.83) to ovoidal (Fig
5.84) with both micro and megalospheric forms; equatorial diameter of the species is
1.5 mm. Proloculus circular and has an internal diameter of 0.06 mm. The chambers
are small and subcircular. There are six whorls at a radius of 1.5 mm.
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Remarks: Scheibner and Speijer, 2009 investigated the Galala Mountains in Egypt
provides an excellent platform-basin transect with deposits spanning the
Paleocene/Eocene boundary. The Late Palaeocene to Early Eocene development of
larger foraminifera is well recorded in the Galala transect, in particular the Tethyan
evolutionary event known as the larger foraminifera turnover (LFT). This turnover
distinguishes Paleocene assemblages dominated by glomalveolinids, miscellanids
and ranikothalids typical for shallow benthic Zone 4 (SBZ4) from those of SBZ5,
dominated by alveolinids, nummulitids, and orbitolitids. Prior to the revision of the
shallow-benthic foraminiferal biozonation (Serra-Kiel et al., 1998) SBZ3 was
established by Hottinger (1960) as the G. primaeva Biozone, defined by the total
range of Glomalveolina primaeva.
Horizon: Lakadong Limestone, Shella formation, Jaintia Group.
Locality: Near Mawlong, East Khasi Hills District, Meghalaya, India
Stratigraphic range (Age): Middle Paleocene
Type Species - Glomalveolina levis (Hottinger, 1960)
Section: 2, Figure: 5.84
Distinguishing characteristics: The test elliptical, diameter 2.06mm x 1.68 mm.
There are seven (7) whorls observed in the specimen. The whorls are elliptical in
outline and wall thick (0.06 mm), septa 0.04 mm thick. Chambers are small and
subspherical in the inner whorls and they are large or subquadrangular in the last
whorls. Proloculus not seen.
Remarks: The Tethyan evolutionary event known as the larger foraminiferal
turnover (LFT) is distinguishes Paleocene assemblages dominated by
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glomalveolinids, miscellanids and ranikothalids typical for shallow benthic Zone 4
(SBZ4) of Serra-Kiel et. al. (1998)
Horizon: Lakadong Limestone, Shella formation, Jaintia Group.
Locality: Near Mawlong, East Khasi Hills District, Meghalaya, India
Stratigraphic range (Age): Middle Paleocene.
5. Textularia sp.
Order - Foraminiferida Eichwald, 1830
Suborder - Textularina Delage and H’erouard, 1896
Superfamily - Textulariacea Ehrenberg, 1838
Family - Textulariidae Ehrenberg, 1838
Subfamily - Textulariinae Ehrenberg, 1838
Genus - Textularia Defrance, 1824
Type species - Textularia sagittula Defrance, 1824
Textularia sagittula Defrance, 1824; p. 177
Textularia sagittula Defrance, 1824 in de Blainville, 1824
Textularia sagittula Defrance; Jorissen, 1987, p. 41, pl. 3, fig. 12
Textularia sagittula Defrance; Rasmussen, 2005, p. 57, pl. 2, fig. 3
Section: 2, Figure: 5.85
Distinguishing characteristics: Test biserial, wedge shaped, two longitudinal rows of
chambers separated by irregular median suture, aperture terminal, chambers are
simple with acute spiral angle.
Remarks: Defrance (1824) reported Textularia sagittula species from Paleocene
rocks of Castel-Arquato, Italy. Mojtahid et. al. (2006) reported Textularia sagittula
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as bio-indicators of drill cutting disposal in tropical east Atlantic outer shelf
environments of Congo, West Africa.
Horizon: Lakadong Limestone, Shella formation, Jaintia Group.
Locality: Near Mawlong, East Khasi Hills District, Meghalaya, India
Stratigraphic range (Age): Paleocene to Upper Eocene
Genus - Textularia, Defrance, 1824
Type species - Textularia barretti Jones and Parker, 1871
Section: 2, Figure: 5.86
Distinguishing characteristics: Test elongate, leaf or wedge shaped, tapering, early
chambers planispirally coiled, rapidly becoming biserial, chambers simple, not
labyrinthic. The measured length of the specimen observed in axial section is 1.0-
1.05 mm and breadth is 0.60-0.70 mm at the end of the test.
Remarks: Gogoi et. al. (2009) reported Textularia barretti from Lakadong
Limestone (Palaeocene) of the Mawsynram area, south Shillong Platue, Meghalaya,
India
Horizon: Lakadong Limestone, Shella formation, Jaintia Group.
Locality: Near Mawlong, East Khasi Hills District, Meghalaya, India
Stratigraphic range (Age): Paleocene to Upper Eocene
Genus - Textularia Defrance, 1824
Type species - Textularia biserial, de Blainville, 1824
Section: 4, Figure: 5.87
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Distinguishing characteristics: Test biserial, wedge shaped, two longitudinal rows of
chambers separated by irregular median suture, aperture terminal, chambers are
simple with acute spiral angle.
Remarks: Gogoi et. al. (2009) reported Textularia biserial from Lakadong
Limestone of the Mawsynram area, south Shillong Platue, Meghalaya, India
Horizon: Umlatdoh Limestone, Shella formation, Jaintia Group.
Locality: Near Mawlong, East khasi Hills District, Meghalaya, India
Stratigraphic range (Age): Paleocene to Upper Eocene
6. Quinoqueloculina sp.
Order – Foraminiferida Eichwald, 1830
Suborder – Miliolina, Delange and Herouard, 1896
Superfamily - Miliolacea, Ehrenberg, 1839
Family – Hauerinidae, Schwager, 1876
Subfamily - Siphonapertinae Saidova, 1975
Genus - Quinoqueloculina, d’Orbigny, 1826
Type Species - Quinoqueloculina seminulum Linne, 1958
Section: 3, Figure: 5.23
Distinguishing characteristics: Test coiled along an elongated axis; spindle shaped in
side view chambers visible. The angular relation between adjacent chambers is 720
Chambers tube shaped, larger ones covering the smaller ones. Margins entire,
chambers increasing outwards from the center, aperture terminal, and circular with
one tooth.
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Remarks: Gogoi et. al., (2009) reported Quinqueloculina seminulum from Lakadong
Limestone of the Mawsynram area, south Shillong Plateau, Meghalaya, India. In the
Gulf of Mexico the Miliolidae are abundant at depths of 30 m (Shifflett, 1961), 70-
100m (the genus Quinqueloculina chiefly in the inner turbulent zone at 20-30 m;
Phleger, 1960), or even down to 150 m (Parker, 1954), and do not descend below
180-220m (Phleger and Parker, 1951).
Horizon: Lakadong Limestone, Shella formation, Jaintia Group.
Locality: Near Mawlong, East Khasi Hills District, Meghalaya, India
Stratigraphic range (Age): Paleocene to Upper Eocene
Genus - Quinoqueloculina, d’Orbigny, 1826
Quinoqueloculina sp.
Section: 3, Figure: 5.24
Distinguishing characteristics: Test coiled along an elongated axis; spindle shaped in
side view chambers visible. The angular relation between adjacent chambers is 720
Chambers tube shaped, larger ones covering the smaller ones. Margins entire,
chambers increasing outwards from the center, aperture terminal, and circular with
one tooth.
Remarks: Gogoi et. al. (2009) reported Quinqueloculina seminulum (Linne 1958)
from Lakadong Limestone of the Mawsynram area, south Shillong Platue,
Meghalaya, India
Horizon: Lakadong Limestone, Shella formation, Jaintia Group.
Locality: Near Mawlong, East Khasi Hills District, Meghalaya, India
Stratigraphic range (Age): Paleocene to Upper Eocene
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7. Triloculina sp.
Order – Foraminiferida Eichwald, 1830
Family – Miliolidea d’ Orbigny, 1839
Subfamily - Miliolinellinae Vella, 1957
Genus - Triloculina d’ Orbigny, 1826
Triloculina sp.
Section: 3, Figure: 5.88
Distinguishing characteristics: Chambers elongated, coiled about the transverse axis
with two chambers in each coil. Later chambers placed on radial planes, 1200 apart,
three chambers taking part in the formation of outer surface of the test, chambers
half a coil in length, wall smooth, aperture round.
Remarks: The Miliolidae are a foraminiferal group having small requirements in
respect of water salinity, for they may be found in both salt and brackish waters, but
their occurrence is frequently restricted to only certain depths and temperatures. In
the contemporary seas they prevail over inner shelf and in open gulfs, in warm and
shallow tropical and subtropical waters, at depths from zero to about 100 m (Sigal,
1952), where they may form 50 per cent or more of the whole population. They
belong chiefly to different species of Quinqueloculina and Triloculina, which are
good indicators of conditions in the vinicity of coasts. The pattern of distribution of
the Miliolidae is only reported from tropical regions, large numbers of miliolids are
a reliable indication of very shallow regions of warm water all over the world.
Horizon: Lakadong Limestone, Shella Formation, Jaintia Group.
Locality: Near Mawlong, East Khasi Hills District, Meghalaya, India
Stratigraphic range (Age): Paleocene to Upper Eocene
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Genus – Triloculina, d’Ordigny, 1826
Triloculina sp.
Section: 4, Figure: 5.89
Distinguishing characteristics: Test free, early chambers quinqueloculine, chambers
elongated, the inner thickness of the adult chamber are ranging from 0.05µm to 0.07
µm which coiled from end to end about a revolving elongate axis, 120o apart, every
thired one superimposed, three chambers visible, wall smooth, aperture round.
Remarks: The pattern of distribution of the Triloculina is generally noted in tropical
regions, shallow regions of warm marine environment.
Horizon: Umlatdoh Limestone, Shella formation, Jaintia Group.
Locality: Near Mawlong, East khasi Hills District, Meghalaya, India
Stratigraphic range (Age): Paleocene to Upper Eocene
Genus - Triloculina d’ Orbigny, 1826
Type species - Triloculina trigonula (Lamarck, 1804), d’ Orbigny, 1826
Triloculina trigonula Lamarck, 1804, p. 351; vol. 9, 1807, pl. 17, fig 4
Triloculina trigonula (Lamarck), d’ Orbigny, 1826, vol. 7, p. 229, pl. 16, figs 5-9
Triloculina trigonula (Lamarck), Schlumberger, 1893, vol. 6, p. 62,
Triloculina trigonula (Lamarck), Cushman, 1917, Bull. 71, pt. 6, p. 65
Section: 4, Figure: 5.90
Distinguishing characteristics: Test free, chambers elongated, the inner thickness of
the adult chamber are ranging from 0.03µm to 0.05 µm that coiled from end to end
about a revolving elongate axis, 120o apart, every thired one superimposed, three
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chambers visible, wall smooth, aperture round and big in size. Test wall smooth,
thickness reaches up to 0.05 mm.
Remarks: The pattern of distribution of the Triloculina trigonula is generally noted
in tropical regions, shallow regions of warm marine environment.
Horizon: Umlatdoh Limestone, Shella formation, Jaintia Group.
Locality: Near Mawlong, East khasi Hills District, Meghalaya, India
Stratigraphic range (Age): Middle Eocene
8. Idalina sp.
Order - Foraminiferida Eichwald, 1830
Family – Hauerinidae Schwager, 1876
Genus – Idalina Munier Chalmas and Schlumberger, 1884
Type Species - Idalina sinjarica Grimsdale, 1952
Idalina sinjarica Grimsdale, 1952, Vol. 1, p. 230, plate 20, Figs. 11-14
Idalina sinjarica Grimsdale, Babazadeh, 2011, Vol. 30 (1), p. 313-319, Fig.3-1
Section: 2 and 3, Figures: 5.58
Distinguishing characteristics: The Megalospheric generation has an elongated
ovoid test with maximum length of 0.70 mm and maximum width of 0.50 mm. The
chambers are arranged bilocularly throughout ontogeny. The megalosphere and
aperture have not been observed.
Remarks: Gogoi et. al. (2009) reported genus-Idalina Munier Chalmas and
Schlumberger, 1884, Idalina sp. from Lakadong Limestone of the Mawsynram area,
south Shillong Platue, Meghalaya, India. Idalina sinjarica – Miscellanea miscella –
Lockhartia haimei assemblage may be at least correlatable with “Shallow benthic
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zones” SBZ3 to SBZ4 by Serra-Kiel et. al., (1998) from the common range of
Idalina sinjarica, Miscellanea primitiva, and Miscellanea miscella, and with the
fauna of the Thanesian Limestone of Dolenja Vas, NW Dinarides (Drobne et. al.
1988) due to the common occurrence of Idalina sinjarica and Kathina selveri.
Further, the present Assemblage in the Lakadong Limestone can partial be
correlated with the basal Larger Foraminiferal Assemblage (LFA1) i.e., Miscellanea
miscella and Ranikothalia nuttalli, in Indian Bassin as Lower Tertiary (Upper
Paleocene, Thanetian) of Letter Stages by Govindan (2003).
Horizon: Lakadong Limestone, Shella formation, Jaintia Group.
Locality: Near Mawlong, East Khasi Hills District of Meghalaya, India.
Stratigraphic range (Age): Upper Paleocene
9. Alveolina sp.
Order - Foraminiferida Eichwald, 1830
Suborder - Miliolina Delage and Herouard, 1896
Superfamily - Miliolacea Ehrenberg 1839
Family - Alveolinidea Ehrenberg, 1839
Genus - Alveolina D'Orbigny, 1826
Type species - Alveolina oblonga d’Orbigny, 1826
Alveolina oblonga d’Orbigny, 1826; Parkinson’s figured specimen, 1420, pl.10, figs
28-31
Alveolina oblonga d'Orbigny, 1826; Tableau methodique, Ann, Sci, Nat. Paris, Ser.
1, Vol. 7, p.306.
Alveolina oblonga d'Orbigny, Hottinger, 1960; p.141, pl. 9, figs. 4-16.
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Section: 3, Figure: 5.25 and 5.26
Distinguishing characteristics: The test is elliptical. In transverse section, the whorls
are very much close to each other and there are 12-15 whorls along the shorter axis.
The form is megalospheric and the initial chamber is sub circular to oval. Septula
alternating is adjacent chambers.
Remarks: Species of Alveolina are abundant in moderate energy shallow water
environmental conditions with significant movement and reworking of bio-clasts.
Matsumaru (1999) identifies microspheric individuals of Alveolina
oblonga d'ORBIGNY from the Lower Eocene (Cuisian) Çayraz Formation in the
Haymana area, southwest of Ankara, Turkey. These foraminifers have a large
number of megalospheric individuals near the periphery of the test, which are
megalospheric embryos fossilized in the process of multiple fission of the
microspheric agamont. Sarma (2005) also identifies this type species from the
Umlatdoh Limestone of Lower tertiary (Late Lower Eocene to Early Middle
Eocene) sequeance in South Jaintia Hills District of Meghalaya, India. A. oblonga, is
originally described from the Lower Eocene of the Paris basin; it is also reported
from the Lower Eocene of France, Italy, Spain and Egypt.
Horizon: Umlatdoh Limestone, Shella formation, Jaintia Group.
Locality: Near Ishamati, East Khasi Hills District of Meghalaya, India.
Stratigraphic range (Age): Late Lower Eocene to Early Middle Eocene
Genus - Alveolina D'Orbigny, 1826
Type Species - Alveolina elliptica (Sowerby, 1840)
http://www.sciencedirect.com/science/article/pii/S0035159899900247
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Fascoilites elliptica Sowerby, 1840, Trans.Geol. Soc. London, Ser.2, Vol.5, p. 329,
pl.18, figs. 17-17a.
Alveolina elliptica (Sowerby), 1925, Nuttall, p.378, pl. 20, figs. 1.
Alveolina elliptica (Sowerby), 1960, Hottinger, p.146, pl. 121, figs. 1-3.
Alveolina elliptica (Sowerby), 1974, Al- Hashimi, p.54, pl. 1, figs. 2-3.
Section: 3 and 4, Figure: 5.27
Distinguishing characteristics: The test ovoidal and cylindrical with bluntly rounded
ends, imperforate, size relatively large attaining (5.0-6.5 mm) in length and (2.5-3
mm) in diameter, length /diameter average ratio is 2:1.In transverse section, the
whorls are very much close to each other and there are 6-8 whorls along the shorter
axis. The form is megalospheric but megalosphere is small, and the initial chamber
is sub circular to oval.
Remarks: Sowerby described Alveolina elliptica species originally from Cutch in
India. It has also reported from Middle Eocene Naoprdan Shally Group of northeast
Iraq. Al-Hashimi and Amer, (1985), described it from the Middle Eocene in the
middle part of the Geli Duhok section, northeastern Iraq. In the present study,
Alveolina elliptica is common in the former Qulqula Conglomerate Formation of the
Middle Eocene age.
Horizon: Umlatdoh Limestone, Shella formation, Jaintia Group.
Locality: Near Ishamati, East Khasi Hills District of Meghalaya, India.
Stratigraphic range (Age): Middle Eocene
Genus - Alveolina D'Orbigny, 1826
Type species - Alveolina dachelansis Schwager, 1883
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Alveolina dachelansis Schwager, 1883
Section: 3 and 4, Figure: 5.28
Distinguishing characteristics: The test is ovoidal. In transverse section, the whorls
are very much close to each other and there are 6-8 whorls along the shorter axis.
The form is megalospheric and the initial chamber is sub circular to oval. Septula
alternating is adjacent chambers.
Remarks: Sarma (2005) also identifies this type genus (Alveolina oblonga) from the
Umlatdoh Limestone of Lower tertiary (Lower Eocene to Middle Eocene) sequeance
in South Jaintia Hills District of Meghalaya, India.
Horizon: Umlatdoh Limestone, Shella formation, Jaintia Group.
Locality: Near Ishamati, East Khasi Hills District, Meghalaya, India
Stratigraphic range (Age): Lower Eocene to Middle Eocene.
Genus - Alveolina D'Orbigny, 1826
Type Species - Alveolina munieri Hottinger, 1960
Alveolina munieri Hottinger, 1960; p.165, pl. 16, figs. 16-21, pl. 17, figs.1-4, pl.18,
figs.1-4, 18.
Section: 3 and 4, Figure: 5.29
Distinguishing characteristics: Test is elongate to cylindrical, with rounded to
subrounded ends, wall porcellaneous, imperforate, size relatively large attaining
(4.5-6mm) in length and (1.0-2.0mm) in diameter, length / diameter average ratio is
4:1, whorl 12-18 in numbers, tightly coiled, basal wall thin equatorially and
thickness towards the poles, chamberlets are numerous and small, supplementary
chamberlets exists in adult whorls, megalospheric is small and elongate.
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Remarks: Alveolina munieri is originally described by Hottinger, (1960) from the
Middle Eocene of north Italy. Al-Hashimi and Amer, (1985), reported this species
from the Middle Eocene in the Avanah Formation of Geli Dohuk, northern Iraq.
Abawi and Sharbazeri, (1987) reported this species as a rare to common in the
middle and upper part of Geli Bessri section and in the middle part of Geli Dohuk
section (Middle Eocene), northern Iraq.
Horizon: Umlatdoh Limestone, Shella formation, Jaintia Group.
Locality: Near Ishamati, East Khasi Hills District, Meghalaya, India
Stratigraphic range (Age): Middle Eocene
Genus - Alveolina D'Orbigny, 1826
Type Species - Alveolina ovulum Stachein Schwager, 1883
Alveolina cf. ovulum Stachein Schwager, 1883, p.95, pl. 24, fig. 13-a-c.
Section: 3 and 4, Figure: 5.30
Distinguishing characteristics: Test is ovate to elongate cylindrical, with rounded to
subrounded ends, wall porcellaneous, imperforate, size relatively large attaining
(3.5-4mm) in length and (1.2-1.8mm) in diameter, length / diameter average ratio is
2.2:1, whorl 7-12 in numbers,chamberlets numerous and in a single layer (6-11) per
mm in the last whorl, megalosphere is oval.
Remarks: Schwager, 1883 from the Middle Eocene of north Italy, originally
describes Alveolina ovulum, and also reported from Upper Paleocene of the Former
Qulqula Conglomerate Formation, Kurdistan Region, and Northeastern Iraq
Horizon: Umlatdoh Limestone, Shella formation, Jaintia Group
Locality: Near Ishamati, East Khasi Hills District, Meghalaya, India
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Stratigraphic range (Age): Middle Eocene
Genus - Alveolina D'Orbigny, 1826
Type Species - Alveolina globosa Leymerie, 1846
Alveolina globosa Leymerie, 1846; p.337-373, pl. 13
Section: 3 and 4, Figure: 5.31
Distinguishing characteristics: Test is elliptical to cylindrical, wall porcellaneous,
imperforate, size relatively large attaining (5-6.0mm) in length and (3-3.5mm) in
diameter, length / diameter ratio is about 2:1, whorl 5-7 in numbers, chamberlets are
numerous in the last whorl, megalosphere is small.
Remarks: Al-Hashimi and Amer, (1985), described A. globosa in Sinjar Formation,
northern Iraq, of Upper Paleocene. In the present study, A. globosa is common in the
Upper Paleocene carbonate rocks of the Shella Formation of Jaintia group.
Horizon: Umlatdoh Limestone, Shella formation, Jaintia Group.
Locality: Near Ishamati, East Khasi Hills District of Meghalaya, India.
Stratigraphic range (Age): Upper Paleocene
Genus - Alveolina D'Orbigny, 1826
Type Species - Alveolina schwageri Checchia-Rispoli
Alveolina schwageri Checchia-Rispoli
Section: 4, Figure: 5.32
Distinguishing characteristics: The test is elliptical. In transverse section, the whorls
are very much close to each other and there are 12-15 whorls along the shorter axis.
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The form is megalospheric and the initial chamber is sub circular to oval. Septula
alternating is adjacent chambers.
Remarks: Erdem et.al, 2007, documented the claystone-limestone succession of
Ilerdian-Cuisian limestones of Southern Eskişehir, Central Turkey, 28 species
of Alveolinad’Orbigny are described and their comparative stratigraphic distribution
with the Alveolina species in the Tethyan Eocene. The the Early Middle Cuisian unit
of the Ilerdian-Cuisian limestones of Southern Eskişehir, Central Turkey, is
represented by G. minutula, A. oblonga, A. schwageri, A. haymanensis, A.
canavarii, A. aff.coudurensis, A. ruetimeyeri, A. muscatensis, A. cremae, A.
bayburtensis and A. lehneri.
Horizon: Prang Limestone, Shella formation, Jaintia Group.
Locality: Near Ishamati, East Khasi Hills District, Meghalaya, India
Stratigraphic range (Age): Lower Eocene to Early Middle Eocene
Genus - Alveolina D'Orbigny, 1826
Type Species - Alveolina solida Hottinger, 1960
Section: 7, Figure: 5.33
Distinguishing characteristics: The test is elliptical. In transverse section, the whorls
are very much close to each other and there are 12-15 whorls along the shorter axis.
The form is megalospheric and the initial chamber is sub circular to oval. Septula
alternating is adjacent chambers.
Remarks: Erdem et. al. (2007) documented the claystone-limestone succession of
Ilerdian-Cuisian limestones of Southern Eskişehir, Central Turkey, 28 species
of Alveolinad’Orbigny are described and their comparative stratigraphic distribution
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with the Alveolina species in the Tethyan Eocene. The the Early Middle Cuisian unit
of the Ilerdian-Cuisian limestones of Southern Eskişehir, Central Turkey, is
represented by G. minutula, A. oblonga, A. schwageri, A. haymanensis, A.
canavarii, A. aff. coudurensis, A. ruetimeyeri, A. muscatensis, A. cremae, A.
bayburtensis and A. lehneri.
Horizon: Prang Limestone, Shella formation, Jaintia Group.
Locality: Near Shella, East Khasi Hills District, Meghalaya, India
Stratigraphic range (Age): Lower Eocene to Early Middle Eocene
Type Species - Alveolina (Glomalveolina) levis
Alveolina (Glomalveolina) levis (Hottinger, 1960)
Section: 2, Figure: 5.34 and 5.35
Distinguishing characteristics: The test is elliptical, diameter 2.06 X 1.68 mm. There
are 8 whorls observed in the specimen. The whorls are elliptical in outline and wall
thick (0.06 mm), septa 0.04 mm thick. Chambers are small and subspherical in the
inner whorls and they are large or subquadrangular in the last whorls. Proloculus not
seen.
Remarks: The Tethyan evolutionary event known as the larger foraminifera turnover
(LFT) is distinguishes Paleocene assemblages dominated by glomalveolinids,
miscellanids and ranikothalids typical for shallow benthic Zone 4 (SBZ4) of Serra-
Kiel et al., 1998.
Horizon: Lakadong Limestone, Shella formation, Jaintia Group.
Locality: Near Mawlong, East Khasi Hills District, Meghalaya, India
Stratigraphic range (Age): Middle Paleocene
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Genus - Alveolina D'Orbigny, 1826
Type Species - Alveolina elliptica (Sowerby)
Alveolina elliptica (Sowerby) var. flosculina Silvestri. Smout A. H., 1954, p. 82,
pl.14, figs.8-12.
Fascoilites elliptica Sowerby, 1840, Trans. Geol. Soc. London, Ser.2, Vol.5, pp.329,
pl.18, figs. 17-17a.
Alveolina elliptica (Sowerby), 1925, Nuttall, p.378, pl. 20, figs. 1.
Alveolina elliptica (Sowerby), 1960, Hottinger, p.146, pl. 121, figs. 1-3.
Alveolina elliptica (Sowerby), 1974, Al- Hashimi, p.54, pl. 1, figs. 2-3.
Section: 4, Figure: 5.36
Distinguishing characteristics: The test elliptical with bluntly rounded ends, wall
porcellaneous, imperforate, size relatively large attaining (4.7-6.5mm) in length and
(2.5-3mm) in diameter, length / diameter 3average ratio is 2:1, whorl 9-15 in number
along the shorter axis, in transverse section, the whorls are very much close to each
other. The form is megalospheric and the initial chamber is sub circular to oval.
Septula alternating is adjacent chambers.
Remarks: Sowerby described this species originally from Cutch in India. It is
reported from the Middle Eocene Chabd beds of southwest Iraq and from Middle
Eocene Naoprdan Shally Group of northeast Iraq. Sharbazheri reported this species
from the Middle Eocene in the Avanah Formation, northern Iraq. Al-Hashimi and
Amer, (1985), Abawi and Sharbazeri, (1987) described it from the Middle Eocene in
the middle part of the Geli Duhok section, northeastern Iraq. In the present study,
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Alveolina elliptica is common in the former Qulqula Conglomerate Formation of the
Middle Eocene age.
Horizon: Prang Limestone, Shella formation, Jaintia Group.
Locality: Near Ishamati, East Khasi Hills District, Meghalaya, India
Stratigraphic range (Age): Middle Eocene
Genus - Alveolina D'Orbigny, 1826
Type Species - Alveolina daniensis Drobne, 1977
Alveolina daniensis Drobne, 1977; vol. 99, p. 20, pl. 1, figs.17-20
Section: 7, Figure: 5.37
Distinguishing characteristics: The test circular, in transverse section, the whorls are
very much close to each other and there are 6-8 whorls. The lines of accretion
parallel to the septum in the basal layer of flosculinized whorls. The form is
megalospheric and the initial chamber is sub circular.
Remarks: Alveolina daniensis, reported from the Lower most Eocene rocks of
Slovenia. Alveolina were common larger benthic foraminifera in the late Paleocene
and Early to Middle Eocene Tethyan (Neotethyan) shallow-water carbonate
platforms (Hottinger 1960). During this timespan, alveolinids represent important
sediment contributors to shallow-water carbonates of the eastern Adriatic cost,
adjacent mainland regions and off -shore wells. In the early Ilerdian (SBZ 5 and
SBZ 6) moderate sized, spherical and flosculinized alveolinids (Alveolina aramaea
Hottinger 1960, A. globosa (Leymerie) 1846, A. daniensis Drobne 1977, A. solida
Hottinger 1960) and the ovoidal to elongated A. vredenburgi Davies and Pinfold
1937 and A. ellipsoidalis Schwager 1883 settled on middle ramp sandy to muddy
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bottoms, from the Pyrenees, to the Northern and Southeastern parts of the PgAdCP,
and eastwards to Turkey. The largest Ilerdian spherical species, A. aramaea
Hottinger 1960, A. daniensis Drobne 1977, A. dedolia Drobne 1977, A. pisella, and
A. brassica, occurred in the eastern (Neo) Tethys, Sirel and Acar (2008).
Horizon: Prang Limestone, Shella formation, Jaintia Group.
Locality: Near Shella, East Khasi Hills District, Meghalaya, India
Stratigraphic range (Age): Lower Eocene
Genus - Alveolina D'Orbigny, 1826
Type Species - Alveolina ellipsoidalis Schwager, 1883
Alveolina ellipsoidalis Schwager, Schwager 1883, pl.25, figs. 1-2,
Alveolina ellipsoidali Hottinger, 1960, p. 64, text figs, 20c, 33a, b, pl. 2, figs. 1-8.
Alveolina ellipsoidali Devoto, 1964, pl. 2, fig. 2.
Alveolina (Alveolina) ellipsoidalis Hottinger, 1974, p. 41, pl. 33, figs. 1-7.
Alveolina ellipsoidali Drobne, 1977, pl. 1, fig. 1-3.
Alveolina ellipsoidali Accordi, Carbone and Pignatti, 1998, pl. 18, fig. 1.
Section: 5, Figure: 5.38 and 5.39
Distinguishing characteristics: Test oval, in axial outline with rounded poles, tightly
coiled, Basal layer very thin, thickening only gradually in axial direction. Growth
stages indistinct. Spherical megalospheric with a diameter of average 0.25mm.
Elengation index of 1.5 in megalospheric specimens. 9-12 whorls. Axial length 3.5
mm, equatorial diameter 2.5 mm. Small sized chamberlets, numerous, rounded in
sections of the early 5 whorls, large and oval in subsequent whorls; chamberlets size
increase with growth. In the last whorl, the chamberlets are more closely spaced
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than in the previous one. At a redious of 1 mm there are 7-8 chamberlets per mm.
Intercalary chamberlets very few.
Remarks: Babazadeh (2011), studied East Nehbandan, Mahrud regions and South
Birjand secctons of Early Paleogene rocks of eastern Iran, the lower part of this
formation consists predominantly of thick graded boulder to pebble conglomerate
and gray calcareous limestones. This part continues with thin-bedded marl at top of
section. The calcareous limestones yield the following benthic foraminifera:
Opertorbitolites douvillei (Nuttall), Alveolina solida Hottinger, Alveolina
ellipsoidalis Schwager, Alveolina pasticillata Schwager, Lockhartia conditi
(Nuttall), Nummulites globulus Leymerie, Assilina laminosa Gill, Discocyclina
dispansa Sowerby,
Discocyclina ranikotensis Davies and Pinfold, Discocyclina sp., Ranikothalia
sindensis (Davies) and miliolids. This spacies represents an index species and is
correlative with SBZ 6 (Ilerdian, Lower Ypresian, and Lower Eocene) of proposed
biozonation of Serra-Kiel et. al. (1998). It indicates an Early Eocene age.
Horizon: Prang Limestone, Shella formation, Jaintia Group.
Locality: Near Ishamati, East Khasi Hills District, Meghalaya, India
Stratigraphic range (Age): Early Eocene
Genus - Alveolina D'Orbigny, 1826
Type Species - Alveolina cf. elliptica (Sowerby),
Alveolina elliptica nuttalli Davies L., 1940, p. 219,221, pl. 12, figs. 1-4.
Alveolina elliptica (Sowerby) var. flosculina Silvestri. Smout A. H., 1954, p. 82,
pl.14, figs.8-12
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Alveolina elliptica nuttalli Davies, Hottinger L., 1960, p. 146, pl. 12, fig. 4.
Alveolina elliptica (Sowerby), Hottinger L., 1960, p. 146, pl. 12, figs. 1-3.
Section: 5, Figures: 5.40 and 5.41
Distinguishing characteristics: The test elliptical, in axial outline with rounded poles,
tightly coiled, wall porcellaneous, imperforate, basal layer very thin, thickening only
gradually in axial direction.Growth stages indistinct. The form is megalospheric and
the initial chamber is sub circular to oval with a diameter of average 0.25mm. size
relatively large attaining (4.5-6.5 mm) in length and (2.5-3.0 mm) in diameter,
length / diameter average ratio is 2:1, whorl 9-12 in number along the shorter axis,
in transverse section, the whorls are very much close to each other. Septula
alternating is adjacent chambers. Small sized chamberlets numerous, rounded in
sections of the early 4 whorls, gradually larger and oval in subsequent whorls;
chamberlets size increase with growth. In the last whorl, the chamberlets are more
closely spaced than in the previous one. At a redious of 1mm, there are 7-8
chamberlets per mm.
Remarks: Babazadeh 2008, studied the Early Eocene succession of bioclastic
limestones of Lower Eocene transgressive succession of Sahlabad province, eastern
Iran, and is marked by the presence of Discocyclina dispansa Sowerby, Lockhartia
conditi (Nuttall), Opertorbitolites douvillei (Nuttall), Alveolina pasticillata
Schwager, Assilina laminose Gill, Alveolina cf. elliptica (Sowerby), etc. and this
assemblage is attributed to the shallow benthic inner shelf environment. This
shallower water orthophragminid assemblage is correlative with SBZ 6 (Ilerdian,
Lower Ypresian, and Lower Eocene) of proposed biozonation of Serra-Kiel et. al.,
(1998). It indicates an Early Eocene age.
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Horizon: Prang Limestone, Shella formation, Jaintia Group.
Locality: Near Ishamati, East Khasi Hills District, Meghalaya, India
Stratigraphic range (Age): Early Eocene
Genus - Alveolina D'Orbigny, 1826
Type Species - Alveolina decipiens Schwager,
Alveolina (Flosculina) decipiens Schwager, Schwager 1883, p. 103, pl.26, fig.1.
Alveolina aff.subpyrenaica (Leymerie)-Hottinger, 1958, fig 8d.
Alveolina decipiens Hottinger, 1960, p. 123, text figs.66a-e, 70g, pl. 8, figs. 1-3.
Alveolina decipiens Gohrbandt and Hottinger, 1967, p. 700, text figs. 3a-g.
Alveolina (Alveolina) decipiens Hottinger, 1974, p. 66, pl. 97, figs. 1-7.
Alveolina (Alveolina) decipiens Drobne, 1977, p.35, pl. 5, figs. 20-21, text fig.17.
Section: 5, Figure: 5.42 and 5.43
Distinguishing characteristics: Megalospheric form. Test ovoidal with rounded
poles, Growth stages indistinct, chamberlets size increase with growth. Early stage
composed of five subspherical tight whorls with thin basal layer; adult stage
moderately elongated and with very thick basal layer. Eight whorls. Chamberlets
large and circular in the axial section of the early five (5) whorls, then irregular in
shape and large. Few intercalary chamberlets in outer whorls. Adult growth stages
irregular in all test characters. No supplementary passages in the basal layer.
Proloculus spherical with a diameter greater than 0.25mm. Axial length 3.4mm and
equatorial diameter 2.2mm. Elongation index close to 1.5
Remarks: This spacies is a particularly variable species difficult to delimit from
others, consequently its range is not very well established, and is correlative with
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SBZ 7-SBZ 9 (Middle Ilerdian, Lower Ypresian, Lower Eocene) of proposed
biozonation of Serra-Kiel et al. (1998). This species is also reported from SBZ 7
zone of Egypt indicates an Middle Ilerdian, Lower Ypresian, Lower Eocene age and
Trentinara formation, Capaccio Vecchio, Southern Apennines, Italy (Vecchio et.al.,
2007)
Horizon: Prang Limestone, Shella formation, Jaintia Group.
Locality: Near Ishamati, East Khasi Hills District, Meghalaya, India
Stratigraphic range (Age): Early Eocene
Genus - Alveolina D'Orbigny, 1826
Type Species - Alveolina cf. dainellii Hottinger, 1960
Alveolina dainellii Hottinger, 1960, Pl. 5, Figs. 12-14; Fig. 53
Alveolina cf. dainellii Hottinger, Nicora & Silva, 1990, Sample 115-715A-19R-1,
Pl. 1, Figs.4 and 6
Section: 7, Figure: 5.44
Distinguishing characteristics: The test is circular to elliptical in transverse section,
common specimens frequently not complete and not oriented. Diameter in the most
complete specimens: 3.5-4 mm. Chamberlets low and wide. Several specimens show
basal thickening and coiling rate close to A. dainellii. The form is megalospheric and
the initial chamber is sub circular to oval.
Remarks: These Paleogene shallow-water larger benthic foraminifers recovered
from Holes 714A and 715A during Ocean Drilling Program (ODP) Leg 115 in the
Indian Ocean located on the eastern margin of the Maldive Ridge (Nicora and Silva,
1990). The biostratigraphic range of defines SBZ 11 (Middle Cuisian, Early Late
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Eocene): Alveolina dainellii, A. aff. canavarii, A. histrica, A. decastroi, A. cremae,
Nummulites praelaevigatus, N. burdigalensis Cantabricus, N. kapeliosi, N. escheri,
N. nitidus, N. archiaci, Assilina laxispira and Discocyclina fortisi simferopolensis
(Serra-Kiel et al., 1998).
Horizon: Prang Limestone, Shella formation, Jaintia Group.
Locality: Near Shella, East Khasi Hills District, Meghalaya, India
Stratigraphic range (Age): Early Late Eocene
Genus - Alveolina D'Orbigny, 1826
Type Species - Alveolina aragonensis Hottinger, 1960
Alveolina aragonensis Hottinger, 1960, PI. 6, Figs. 5-10; Fig. 60 (b-f);
Alveolina aragonensis Hottinger, Drobne, 1977, PI. 5
Alveolina aragonensis Hottinger, Nicora and Silva, 1990, Sample 115-715A-21R,
PI. 3, Fig.1
Section: 5, Figure: 5.45
Distinguishing characteristics: Test oval, in axial outline with rounded poles, tightly
coiled, Basal layer very thin, thickening only gradually in axial direction. Growth
stages are indistinct. Spherical megalospheric and the axial length 5mm, equatorial
diameter 3.5mm; length/width ratio: 1.5, whorls 9-16. Small sized chamberlets,
numerous, rounded in sections of the early 5 whorls, large and oval in subsequent
whorls; chamberlets size increase with growth. In the last whorl, the chamberlets are
more closely spaced than in the previous one. At a redious of 1 mm there are 7-8
chamberlets per mm. Intercalary chamberlets very few.
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Remarks: The specimen displays narrow and high chamberlets; a moderately, rather
regularly increasing spire, with a thin basal thickening in the equatorial region and
slightly more development at the poles; and a general shape that is a little more
fusiform than the typical A. aragonensis. Erdem et. al. (2007), described the
claystone-limestone succession of Ilerdian-Cuisian limestones of Southern
Eskişehir, Central Turkey, and their comparative stratigraphic distribution with
abundant benthic foraminifera, particularly species of Alveolina d’Orbigny (1826) of
Tethyan Eocene time. The Ilerdian unit of the study area is characterized
by Alveolina species, such as Glomalveolina lepidula, G. minutula, G. karsica, A.
vredenburgi, A. ellipsoidalis, A. avellana, A. aff. minervensis, A. dedolia, A.
moussoulensis, A. subpyrenaica, A. laxa, A. aragonensis, A. varians, A.
ilerdensis, A. trempina, A. citrea, A. pisella and A. decipiens.
Horizon: Prang Limestone, Shella formation, Jaintia Group.
Locality: Near Ishamati, East Khasi Hills District, Meghalaya, India
Stratigraphic range (Age): Early Eocene to Middle Eocene
Genus - Alveolina D'Orbigny, 1826;
Type Species - Alveolina nuttalli (Davies, 1940)
Alveolina elliptica nuttalli Davies, 1940, p. 219- 220, pl. 12, figs. 1-4
Alveolina elliptica flosculina Silvestri, 1954, Smout, p. 82-83, pl.14, figs. 8-12
Alveolina nuttalli (Davies), 1993, Samanta, p. 65-72, pl.10, figs. 1-5; pl. 11, figs.2-3.
Section: 5, Figure: 5.46
Distinguishing characteristics: The shape of the test is ovoid with rounded poles.
Axial diameter ranges from 4mm to 5.5mm, equatorial diameter from 2.6mm to
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3.8mm and index of elongation from 1.44 to 1.54. All the sections and incomplete
specimens examined were megalospheric. The shell of the species composed of
three growth periods. The spheric megalosphere (its diameter ranges from 0.170mm
to 0.185mm) is followed by tight-coiled ovoid 5-7 whorls of the nepionic stage. The
number of the flosculinized whorls ranges from 2 to 3. The ovoid 7-8 whorls of the
senile period are coiled tightly in the axial as well as the equatorial spire. The size of
the chamberlets increase gradually from the proloculus to the last whorl; their cross
section are generally subspheric.
Remarks: Four specimens collected from the upper Kirthar beds (middle Eocene) of
north-west India were described and figured as Alveolina elliptica (Sowerby) nuttalli
Davies by Davies (1940), in spite of the fact that the alveolinid association consists
of different two species. The first alveolinid species illustrated in Davies (1940)
resembles A. elliptica Sowerby by large test with tightly coiled numereous whorls
Hottinger (1960). The second species A. elliptica Nuttalli figured in Davies (1940)
have an ovoid test including the ovoid nepionic