Catalog Number: CG-0090

This gastropod has a highly probable Identification. I have confirmation that Trepospira sphaerulata is found in this and nearby limestone layers. Based on the nodes visible on the top of the last whorl, a local fossil gastropod expert gives this as a likely identification. This specimen comes from the Pine Creek Limestone locality which has been the source material for many of my recent posts.

The only fact keeping me from being sure is the lack of suture ornamentation. These should display as regular raised nodes. However, the fact that this is a very flat, wide shell helps. The spire is visible as small and only raised in the very center.

Focus stacked photo of Trepospira sphaerulata

Example showing ornamentation from the late 1800’s

The example below was regarded as a perfect specimen. The suture ornamentation is very apparent.

Trepospira sphaerulata from Geological and Natural History Survey of Minnesota, Volume III, Part II, Page 1081.

Additional Photos of CG-0090

Specimen (right) with several other that may be of the same genus.

References for Trepospira sphaerulata