6.5" Fossil Capelin Fish (Mallotus) Nodule - Ontario

These are Capelin fish fossils of the species Mallotus villosus preserved inside of a concretion, collected from Ontario, Canada. These uniquely preserved fish have beautifully preserved bone structure and are found by cracking open the hard concretions. Only the pictured half of this concretion is included. This is an old collection piece.

These nodules formed within the Pleistocene-aged Leda Clay. This clay formation occurred as a result of an inland sea known as the Champlain Sea, formed from massive glaciers. The weight of these glaciers caused the Earth's crust to sink, which proceeded to be filled in by the Atlantic Ocean following the recession of the glaciers. These waters were home to a variety of marine fauna, including the Capelin fish.