SILURIAN-DEVONIAN DISCONFORMITY IN SOUTHERN ONTARIO.

The sub-Devonian (Gedinnian) disconformity in southern Ontario is developed upon the Upper Silurian Bertie Formation. Two erosion surfaces are recognizable: pre- and post-Oriskany sandstone. An extensive system of Silurian joints and fractures is developed within the Bertie beds. Analysis of sedimentological and paleontological data leads to the recognition of a marine transgressive-regressive sequence in which two distinct subaerial disconformities are present.