Showing posts with label Brownsport Formation. Show all posts
Showing posts with label Brownsport Formation. Show all posts

Thursday, August 21, 2014

Merista tennesseensis brachiopod from Tennessee

Today I have a brachiopod specimen called Merista tennesseensis from the Silurian (Wenlock epoch) aged Bob Limestone member of the Brownsport Formation. It was found near Bath Springs, TN. I was confused when I saw the name at first because of the similarity to Meristella (let alone Meristina!) but it is a completely different genus.

Brachial valve
Anterior
Pedicle valve
Posterior
Profile

I found a couple of records on Yale's online collection of fossils in their Peabody Museum for Merista tennesseensis. This one was the only one that had a decent specimen picture.

Tuesday, August 19, 2014

Atrypa tennesseensis brachiopod from Tennessee

Another brachiopod from the Bob Limestone member of the Brownsport Formation (Silurian, Wenlock Epoch) is Atrypa tennesseensis. Atyrpa is a very common brachiopod in the Silurian and Devonian. It appears that this species can be distinguished from the more widely know A. reticularis species by the lesser number of rays ornamenting the shell. In fact, to my eyes, the shell ornamentation looks more like a Spinatrypa type.






The specimen above came from the Bath Springs area of Tennessee. Compare this to A. reticularis from the Lockport limestone of New York or A. oklahomensis from the Haragan formation of Oklahoma.

Sunday, August 17, 2014

Thecia minor coral from Tennessee

Another neat coral from the Silurian is this Thecia minor from the Lobelville Fm member of the Brownsport Formation (Ludlow epoch?) near Lobelville, TN. It has a flat, sheet like or encrusting growth pattern and the individual corallites have radial line growths around them. Note the grooves that connect between the corallites. They are called Mural Pores and were used as a nutrient transfer system among the colony.





I've found something similar from the Louisville Limestone in Kentucky that is called Romingerella major.