Saturday, April 19, 2014

Megistocrinus sp. crinoid calyx from Marilla, NY

It's not a great fossil but the specimen below is one of the few Crinoid calyxes that I have found. It's a weathered Megistocrinus sp. calyx that I found in the Deep Run mbr. of the Moscow formation.I found it in a creekside exposure of Buffalo Creek near Marilla, NY.

Here is the matrix with the bottom of the calyx sticking out on the right hand side.

A closer view of the side where you can see some of the geometry of the plates that make up the calyx. along the top of the calyx are some round knobs where the arms once were attached.

Another side view
A view of the bottom with the basal plates where the stem would have attached.
The patterns on the calyx plates are not those that would have been seen in life. Since the specimen has eroded due to exposure to the elements the marks on the plates are more likely a crystallization pattern that is preferentially weathered.

The Deep Run mbr. of the Moscow Fm. is stratigraphically older than the Windom shale and is not found along Lake Erie. The town of Marilla is located about 15 miles east of Buffalo and the exposure there of the Deep Run Mbr. is only about a foot thick. I need to find another exposure farther east so that I can explore this rock unit more.

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