Thursday, January 23, 2014

Amplexiphyllum hamiltoniae coral from the Windom Shale

The next most common coral to be found in the Wanakah/Windom shale is Amplexiphyllum hamiltoniae. This coral is most easily identified by it's length, consistently narrow diameter and tendency of the corallite to show bends. Unlike Stereolasma rectum, this coral seemed to grow higher from the sea floor and so would be subject to toppling by wave base or current action.

Specimen #1 is small but shows the consistent diameter growth pattern.

Specimen #2 is still in matrix and shows a particularly long specimen. This is often the best way to collect these corals as otherwise they are found as fragments within the loose shale as they erode out.

Specimen #3 is also preserved in the matrix but is not as photogenic as the previous specimens.

All three specimens shown were collected from the Windom shale mbr. of the Moscow Formation (Smoke Creek Trilobite bed most likely) at the Penn Dixie site in Blasdell, NY.  Both the Moscow formation and the Wanakah formation are Devonian (Givetian stage) in age.

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