While looking at a chunk of Waldron Shale that had a crinoid calyx, the shale split revealing a small fossil fragment. This image was taken while it was under a microscope with a field of view of about 4 mm.
The Strophostylus cyclostomus was described by James Hall in the 1881 Indiana Geological Survey (pages 316-317; Plate 31 Figure 13). "An enlargement of the surface-striae of a full-grown specimen, showing the transverse striae of growth, and the finer revolving lines."
Monday, October 12, 2015
Sunday, October 11, 2015
This brachiopod imprint is an Orthotetes keokuk found in the Borden Formation of Floyd County, Indiana, USA. The fossil is from the Mississippian Period. It measures about 7.3 cm wide and 5 cm tall.
Thanks to Kenny for letting me photograph it.