New Paris Quarry, Bedford co. PA

[SharkySarah]

I was super lucky the other week to be invited to the New Paris Quarry in Bedford co. PA. The owner of the quarry is super nice and knowledgeable. He handed out a geology and ID sheet specific to his quarry. 
 

 

according to that sheet, I spent the day in the Old Port formation. The rock was a very hard limestone. I tried to get some of these brachiopods out of the rock but my rock hammer just dented the rocks. (Keyser fm. Is also present in the quarry along with calcite and fluorite) 

 

Here are some calcite pieces: 

 

some of the fossils I couldn’t get out:

 

 

at the end of the day, it was a lot of work for only some reward. Limestone is very hard and the preservation is lack luster. A majority of the finds are brachiopods with the most being Leptaena. Trilobites were super hard to come by, as a group only finding 4 of them. Some  of my finds:

 

a worn brachiopod of unknown genus

Crinoids 

 

my favorite brachiopod rock that sadly isn’t on the ID sheet so I don’t know the name 

 

The best find- Symphoria trilobite 

 

Leptaena brachiopod 

 

this is a weird one. Either coral, mud ripples or something else ?

 

either bryozoan or minerals 

 

 

[NickG]

Is the contact between the Old Port and Onondaga accessible there?

[SharkySarah]

@NickGnot that I’ve read or seen. 

[EMP]

12 hours ago, NickG said:

Is the contact between the Old Port and Onondaga accessible there?

I think in that part of PA the limestone of the Old Port directly underlies the Oriskany Sandstone instead. 

[NickG]

16 minutes ago, EMP said:

I think in that part of PA the limestone of the Old Port directly underlies the Oriskany Sandstone instead. 

Do you mean the Ridgeley Member (sandstone) is exposed there? My understanding is where the Ridgeley Member isn't present, that the Shriver Chert is instead. Is this reflective of what you mean? The matrix and some of the fauna definitely looks similar to what I've seen in the New Creek Limestone in the type section. I'm not 100% familiar with the Old Port vs its southern lateral equivalents in western MD/WV/VA. 

 

#22 looks like messed up sponges. I've seen similar preservation in the New Creek Limestone at the type section.

 

#24 resembles Strophodonta. Get these papers tho:

Bowen, 1966, Brachiopods and stratigraphy of the Elbow Ridge Sandstone (Lower Devonian) of Pennsylvanian, Maryland, and West Virginia: Journal of Paleontology 40, 1051--1062.

Bowen, 1967, Brachiopoda of the Keyser Limestone (Silurian-Devonian) of Maryland and adjacent areas. Geological Society of America Memoir 102.

 

Nick

[EMP]

4 hours ago, NickG said:

Do you mean the Ridgeley Member (sandstone) is exposed there? My understanding is where the Ridgeley Member isn't present, that the Shriver Chert is instead. Is this reflective of what you mean? The matrix and some of the fauna definitely looks similar to what I've seen in the New Creek Limestone in the type section. I'm not 100% familiar with the Old Port vs its southern lateral equivalents in western MD/WV/VA. 

 

#22 looks like messed up sponges. I've seen similar preservation in the New Creek Limestone at the type section.

 

#24 resembles Strophodonta. Get these papers tho:

Bowen, 1966, Brachiopods and stratigraphy of the Elbow Ridge Sandstone (Lower Devonian) of Pennsylvanian, Maryland, and West Virginia: Journal of Paleontology 40, 1051--1062.

Bowen, 1967, Brachiopoda of the Keyser Limestone (Silurian-Devonian) of Maryland and adjacent areas. Geological Society of America Memoir 102.

 

Nick

My understanding is that the Old Port name isn’t used south of central PA, and the names Helderberg Group and Oriskany Sandstone are instead applied to the lower Devonian sequence up to the base of the Needmore Shale, including the Shriver Chert.  
 

Basically the sequence is:

 

New Creek Limestone (mapped as the undifferentiated Helderberg Group in Maryland)

 

Corriganville Limestone (mapped as the undifferentiated Helderberg Group in Maryland)

 

Mandata Member (mapped as the undifferentiated Helderberg Group in Maryland)

 

Shriver Chert (mapped as part of the Oriskany Sandstone in Maryland)

 

Ridgeley Sandstone (mapped as the Oriskany Sandstone in Maryland)

 

Basically in Maryland and I believe southern PA the units are actually mapped as the Helderberg Group and Oriskany Sandstone, and thus the upper contact of the limestones of the Helderberg Group (or Old Port Formation as the OP referred to it as) is with the Oriskany Sandstone and not the Onondaga. I’ve never heard the Onondaga name applied to any member of the Helderberg or Oriskany except in historical contexts. 
 

I don’t know if the Oriskany is exposed in the quarry or not, but from the photos it looks like it’s from atop a ridge and since the Oriskany is a major ridge forming unit in that part of the Alleghenies I wouldn’t be surprised if the Oriskany was present, albeit outside the quarry’s boundaries. The Shriver is technically between the Oriskany and Helderberg but IIRC the Shriver is not geographically continuous and is locally absent so I wouldn’t be surprised if it wasn’t exposed.

 

At any rate too the Onondaga is predominantly a nonclastic unit whereas the stratigraphic equivalents in southern PA and Maryland are clastic units belonging to the Oriskany Sandstone and Needmore Shale. 
 

As for item 22 and the one above, could they be ostracods? 

[SharkySarah]

@NickGthanks for the paper suggestions. I’ll have to look more later but haven’t found them yet. I agree with the brachiopod. Thanks! 
 

@EMP I don’t think they’re ostracods. The ostracods I’m familiar with from the Moscow fm. are a lot smaller than  these. 

[NickG]

No. I didn’t mean to imply the Onondaga is a submember of the Helderberg!

 

also, while they’re mapped together on geologic maps, there’s enough lit to understand the Helderberg and Oriskany members in the field. The basal part of the Onondaga is shale, and the Needmore Formation down in WV is basally shale but as you move east, they are more calcareous shales and then up-section the Selinsgrove Limestone forms the top and is capped by the Marcellus. If you go west, the Needmore is mostly shale with seemingly no calcareous shales or any limestones straight into the Marcellus. 

[NickG]

4 minutes ago, SharkySarah said:

@NickGthanks for the paper suggestions. I’ll have to look more later but haven’t found them yet. I agree with the brachiopod. Thanks! 
 

@EMP I don’t think they’re ostracods. The ostracods I’m familiar with from the Moscow fm. are a lot smaller than  these. 

Can you prep some of the surface around the fossils to see what their depth is? My examples in the New Creek limestone are packed up but I will try to find them this weekend.