Notes
| The light areas on the map represent dry land during the Silurian period of the Palaeozoic Era. The Palaeozoic Era was the geological era containing the oldest forms of highly organized life, including reptiles and seed-bearing plants, dating back from 500 million to 350 million years ago. The Silurian Period, dates back 430 to 390 million years. Niagara District sedimentary deposits, mostly sandstone, shale and marine limestone, were laid down in the Silurian Period. This is the third period in geological time during the Palaezoic Era. |