Waldron Shale Ostracod Fossil

Here is a picture of an ostracode microfossil found in the Waldron Shale of Clark County, Indiana, USA. It is about 420 million years old which puts it in the Silurian Period.

After looking at the paper entitled "A Study of the Ostracoda Fauna of the Waldron Shale, Flat Rock Creek, St. Paul, Indiana" by Horace Noble Coryell and Marjorie Williamson published by the The American Museum of Natural History (New York City, Number 870) on July 6, 1936, it appears to be some sort of Cornulina sp.  See their paper here: WEB LINK.

Thanks to Kenny for the picture.