Paleontology and geology
During the Cambrian, most of Alaska as we know it today had not yet begun to assemble. Shallow marine conditions were widespread, although the record of these rocks is rare and scattered. The best record of these marine rocks is found in the east central part of the state, near the present Canadian border. There we find evidence of a range of marine environments, including an extensive carbonate platform derived from sponges, coral-like animals, molluscs, and associated organisms, down the continental slope, and out onto the deep ocean floor. Fossil evidence also includes trilobites, archaeocyaths, brachiopods, and numerous trace fossils.