Sunday, March 3, 2013

Favosites Growing on Crinoid Stem

A Favosites coral growing around the stem of a crinoid. This type of growth appears to have been typical for this coral. Fossil was found in the Waldron Shale of Clark County, Indiana. It grew in the Silurian Period about 420 million years ago.

Below is an illustration from Plate 17 (Figure 9) Indiana Department of Geology and Natural History Eleventh Annual Report John Collett State Geologist 1881. It shows a Favosites coral growing on a Eucalyptocrinus crassus stem.