Trace fossils from near Avoca NY

Among the rocks in the large road cut north of Avoca, NY on I-390 (that I blogged about a couple of days ago) were these trace fossils. The rocks are of Upper Devonian age (Fransian stage) from the Gardeau formation of the West Falls Group. At that time the shore line was just east of Avoca and the paleoenvironment was a near shore shelf that was very close to stream and river deltas. These trace fossils probably represent worms burrowing through the substrate in search of food particles.

This one appears to be the top of a vertical burrow where the worm living inside would extend itself out and sweep the nearby sediment for food. The pinwheel like pattern could be an example of the creature systematically covering all the area around the burrow.

These traces are of horizontal burrows, possibly in a very shallow, tidal environment.

Cariniferella tioga from Avoca NY

While on the road this summer en route to a collecting site I stopped off at a road cut just north of Avoca, NY on I-390. It is a large cut that exposes rocks of Upper Devonian age (Fransian stage) from the Gardeau formation of the West Falls Group. Much of the fallen rock that is exposed at the base of the cut is barren but I did find occasional fossils. This was perhaps the best specimen I found and is the brachiopod Cariniferella tioga. The oval shape of the shell reminded me of Schizophoria sp. but the radial ribs were too coarse for that ID to be correct. Schizophoria does not have a sulcus on the brachial valve either. It was after I received my copy of the new book "Field Guide to the Devonian Fossils of New York" by Karl Wilson that I realized I had a Cariniferella fossil.

Brachial valve

Anterior

Pedicle valve

Posterior - note the small, triangular interarea

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