The most common Brachiopod to be found in the Collingswood member of the Whitby formation is Lingula corbourgensis. It is an inarticulate Brachiopod with a phosphatic shell and can get relatively large. Below are several examples that occur on slabs that I've split.
The Whitby formation is Ordovician in age (late Ordovician, Katian/Mohawkian stage).
fossils were 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. 117 to help identify these