Jesse Jones

11/17/15

Field Report

Site 1 Route 15:

First step out of the van was a very vertical rock cut facing the west. We parked right beside a

unit of sedimentary rock that looked very brittle to the eye. There were many layers upon layers

when examining the structure of the formation. To the south of where we park were a red

sedimentary rock called “rock beds”. There were two different formation at this site which made

it an intriguing area of study. Over the course of the 20-30 minutes many people were finding all

sorts of fossil fragments some that were still in tacked and others that broke away from the rock

unit quite nicely. The two formation of study at this first stop were the Lock Haven formation

which contained ruminates of shallow marine fossils that were about 30-90 meter thick

according to Bradford writer of Roadside Geology of Pennsylvanian. Mainly a Devonian Lock

Haven formation with a contact of overlying Catskill formation (Bradford 127). Taking note to

the south, mostly Catskill formation, dominantly reddish, sometimes red brick or maroon, to

greenish gray, cross bedded sandstones and the thin shale’s (Bradford 127) these formations,

both the Lock Haven and Catskill red beds formed during the Devonian period ranging from 400

million years old to 370 million years old. From North to South, the Lock Haven formation was

to the north ranging in height of 20-50 meters at the rock cut location we were observing.

Moving to the south this shale and mud/silt stone structure continued to be more of a sandstone

based rock structure throughout having no real vast fossil formation and was quite abrupt when

walking up to it from the Lock Haven Formation. With the Arcadian Mountains to the east the

deposition of this location was quite low. From what we saw starting from the south of the rock

cut was higher ground predominantly dry environments. Heading north the environment was

seen as a lower or shallow marine environment with the assortment of marine type fossils and

vegetation throughout the rock cut.

Figure 1: Coalified Wood or

Plant Frag.

Figure 2: A small Cemerotochia

Figure 3: Rhipidomella

Site 2 Mutton Creek Road Cut; Route 328:

The second rock exposure wasn’t as good as the first due to the time of year. Being that this rock

cut was located in a forest there was lots of leaves on the ground covering up majority of the

rock exposure. Taking note this site was across from a creek running east to west. From what the

Roadside Geology of Pennsylvania there used to be an old railroad put in place along this route

and over time Mutton Creek’s original direction of flow was along this rock cut but now has

moved either naturally to the south 50 yards or was diverted by man. With that said, this

formation is a part of the Lock Haven formation. Being north, this part of the Lock Haven

formation doesn’t have the depth compared to the road cut a couple miles south of this cut. The

sub unit is called the Westfalls Group while the main formation is the Lock Haven. Being that

the first site was a shallow portion of the lock haven formation as the formation moved to the

north the waters were interpreted has deeper waters do to the different types of fossil groupings

like Pelecypods, Brachiopods, and Horn Coral. Another give away for this being a location of

probable deep marine environments is the type of sediments the rocks are made of as well.

Figure 4: Coalified plant material

Figure 5: Coalified plant material

(Lower Center), Portion of Horizontal burrow (Upper center)

Figure 6: Small

Aviculopectem (Lower Right), Two Rhipidomella (Lower Left and Center), Small

Whidbormella (Upper Right)

Bibliography

Berg, T. (1981). Guidebook for the 46th Annual Field Conference of Pennsylvania Geologists:

Geology of Tioga and Bedford Counties, Pennsylvania. Harrisburg, PA: Distributed by Field

Conference of Pennsylvania Geologists c/o Dept. of Environmental Resources, Bureau of

Topographic and Geologic Survey.

VanDiver, B. (1990). Roadside geology of Pennsylvania. Missoula, Mont.: Mountain Press Pub.