1. Part of Niagara Peninsula, Ontario, showing structure contours drawn on top of the Clinton formation and positions of wells drilled to obtain natural gas [cartographic material] Yale Public content 1940. 2012-06-07T18:06:49Z. 2012-06-13T15:05:19Z. Canada. Bureau of Geology and Topography. Geological Survey. English. Public. Ontario and Niagara Peninsula.