undifferentiated rock units

Paleontology and geology

For most of the Silurian, exposed land was far to the east, and all of British Columbia was underwater. The northeastern part of the province had lagoons and very shallow areas. From there, the continental shelf extended over most of the province. Over time, the western end of the shelf began to dip down, and the deeper waters of the continental slope and ocean basin were near the middle of the province. The shallow water limestones have yielded stromatolite fossils, the deeper shales and siltstones produced sponges, and conodonts have been found in rocks from all depths. In the Late Silurian, the seas retreated, exposing much of the province, and many older rocks were eroded. A few exposures remain in the Rocky Mountains, particularly in the east, but they are very small. Other more detailed maps may show more Silurian rocks.