undifferentiated rock units

Paleontology and geology

In the Silurian, much of the province was above sea level and exposed to erosion. Shallow seas covered the continental shelf in the west and to the south. Many of the sandstones, mudstones, limestones, and dolostones deposited on the shelf have been removed by erosion. Some rocks are preserved below the surface under younger rocks in the southeast, and a few exposures can be seen in the Rocky Mountains. These exposures are too small to be found on this map, but other more detailed maps may include them.