undifferentiated rock units

Paleontology and geology

In the Cambrian, northern Alberta was above sea level, and sediments eroding off the land accumulated in the shallow seas that covered the rest of the province. Sands and muds were deposited closer to land, and limestones formed in the south and west on the continental shelf. In the Late Cambrian, a peninsula emerged in the southwest, dividing the shelf in two. Trilobites, brachiopods, conodonts, molluscs, and echinoderms lived in these warm, tropical seas. Most of the Cambrian rocks in Alberta are found below the surface, covered by younger deposits, but exposures can be found in the Rocky Mountains in the southwest.