Sinuites angularis gastropod from the Coburg Formation

Gastropod fossils from the Paleozoic tend to not have any shell preserved with some exceptions to that rule. In this case, it is true. Sinuites angularis is a common gastropod from the Coburg formation and is a planispiral snail. That means that it's shell forms a spiral that wraps upon itself but stays in the same plane (it doesn't curve off in one direction or another. Generally these look like rounded blobs when found in the field and some searching will yield good specimens.  As it is so blob like, the pictures below are the best I can do to try and show you the specimen from different angles.

The Coburg formation is Ordovician in age (late Ordovician, Katian/Mohawkian stage).
This fossil was collected from the St. Mary's Limestone Quarry in Bowmanville, Ontario. I used William Hessin's book "South Central Ontario Fossils", 2009, Self Published, pg. 135 to help identify it.