Sunday, May 17, 2009

Devonian Heliophyllum Horn Corals

Here are two specimens found in Clark County, Indiana in the Jeffersonville Limestone. They are both Heliophyllum sp. with the second picture of one budding another horn coral.

Platystrophia Brachiopod with Cornulites

UPDATED: I originally posted this as a small horn coral attached to the shell but a series of anonymous comments set me on the correct course. What I thought was a horn coral was really a Cornulites. Thank you to the person(s) who gave me the correct identification.

All the heavy rains have provided great collecting at the road cuts outside the city. The Ordovician fossils that are the most common is the brachiopod. This brachiopod is a Platystrophia of some type. What I found interesting was this Cornulites that anchored itself in the groove of the brachiopod shell. It is thought to be a tubicolous annelid worm that orientated itself for feeding. Since this one was pointing toward the shell opening, it probably attached and grew there while the brachiopod was still alive.

This other Cornulites it placed in the opposite direction pointing toward the bottom of the shell.