Note 20 — Chapter III

Walcott and Matthew record more than 160 species of 67 genera, including Sponges, Zoophytes, Echinoderms, Brachiopods, Bivalve and Univalve shellfishes, Trilobites and other Crustaceans from the Lower Cambrian of the United States of America and Canada alone; and these are but a portion of the inhabitants of the early Cambrian seas. There is a rich Scandinavian fauna of the same early date, and in England and Wales, Sailer, Hicks and Lapworth have described many fossils of the basal Cambrian. From year to year, also, discoveries of fossil remains are being made, both in America and Europe, in beds of older date than those previously known to be fossiliferous. At present, however, these remains are still few and imperfectly known, and it is not in all cases certain whether the beds in which they occur are pre-Cambrian or belong to the lowest members of that great system. It is unfortunate that so many of the strata between the Laurentian and the Cambrian seem to be of a character little likely to contain fossils; being littoral deposits produced in times of much physical disturbance. Yet there must have been contemporaneous beds of a different character, which may yet be discovered.