Friday, December 30, 2011

Pustulatia pustulosa from the Mahantango fm?

From the same pit that I found the Dechenella trilobite I also found these brachiopods that I think are Pustulatia pustulosa. They are slightly distorted due to geologic forces but seem to match the shape of the brachial valve of specimens that I've found in the Kashong shale of New York as seen in This Post.

This is the first time I've found this species within the Mahantango. It is a known (and supposedly common) species within the Mahantango based on it's inclusion on one of the Devonian plates within the book "Fossil collecting in Pennsylvania" by Donald Hoskins (PA Geological Survey publication G40).


  1. Dave - Without a doubt this is "Pustulatia pustulosa" Hall. Good pictures can be found in "Devonian Paleontology of New York" Linsley - Middle Devonian Plate 95 Figures 35 - 44. Also, "Stratigraphy and Paleontology of the Mahantango Formation in South-Central Pennsylvania Report 48" - See Plate 10 Figure 14 -18. I've found a number of these in a pit on route 74 south of where route 17 (Ickesburg, PA) cuts route 74. This pit is near a logging /mulch operation. The most common brachiopod was "Emanuella praeumbonata" and the second most common brachiopod was "Pustulatia pustulosa". The other fossils I found suggested that this was Middle Devonian /Hamilton Group / Mahantango FM - Possibly Centerfield. Regards - Jack Kesling

  2. Jack - Sounds like we were collecting in the same pit. The only problem is Rote 17 and 74 don't intersect. The quarry is just south of Ickesburg on 74 near the intersection with Waggoners gap road.

    I was thinking there could possibly be the Centerfield mbr. exposed but it could also be the Tully equivalent since the contact with the Trimmers Rock fm. is right there. Check out my post from the 28th: and I describe the quarry and geology. -Dave

  3. Dave - Yes - after looking at your geological photo map, we were indeed working the same quarry. I pulled out the PA road map. I was West of the site, drove down 850 which connected with 17 and went down 17 to Ickesberg - 17 cuts right across 74 at Ickesberg (17 continues on the other side of Ickesberg). I only spent about two hours at the site. The Hamilton /Mahantango rock was mined out and placed in the front of the quarry near the packing, but there was considerable Mahantango on the North East end of the quarry. The back of the quarry was light clay like shale and looked like typical Tully I'm use too. Note: I found no fossils in this part of the quarry. I did not have time to hunt the South East /South West end of the quarry so I have no idea if it contained fossils. - Jack