. Correlation papers ; Cambrian. Geology, Stratigraphic; Geology. 274 THE CAMBRIAN. [bull. 81. It is the record of the accumulation of sediments in a gradually deep- ening sea. The eastern Massachusetts section is largely formed of shale, except in the lower part, where a small proportion of limestone occurs in the Olencllus zone, much as in the southeastern Newfoundland section. The great thickness of shales referred to the Cambrian in Nova Scotia, Maine, and New Hampshire probably represents much more than the Cambrian group, or it may be entirely a pre-Cambrian forma- tion or a post-Cambria
. Correlation papers ; Cambrian. Geology, Stratigraphic; Geology. 274 THE CAMBRIAN. [bull. 81. It is the record of the accumulation of sediments in a gradually deep- ening sea. The eastern Massachusetts section is largely formed of shale, except in the lower part, where a small proportion of limestone occurs in the Olencllus zone, much as in the southeastern Newfoundland section. The great thickness of shales referred to the Cambrian in Nova Scotia, Maine, and New Hampshire probably represents much more than the Cambrian group, or it may be entirely a pre-Cambrian forma- tion or a post-Cambrian formation. It is only probable that tbey are of Cambrian age. They may represent deep-water accumulations in which no organic remains were buried. As a whole, we may regard the Atlantic Coast Province, during Cam- brian time, as including bays and the adjacent shores of the Algonkian land, in and along which sediments, mostly of an argillaceous and arenaceous character, accumulated. The relative level of the sea bed varied, but in the main the depression greatly exceeded the elevation. The depth of water in which the sediments forming the limestones and shales accumulated was probably considerable, but not a deep sea in the present sense of the term. A few hundred or a thousand feet on a gradually sinking sea bed (in relation to the coast line) would give the required conditions. From the character of the sediments and tbe faunas it is probable that laud barriers existed to the eastward of the present coast, and that none of the deposits were accumulated oft" the shore facing the open ocean. As left by erosion the Lower Cambrian now occurs on the Labrador coast, on the western and eastern sides of Newfoundland, in New Brunswick, and eastern Massachusetts. The Mid- dle Cambrian has been recognized on the eastern coast of Newfoundland, in New Brunswick, and eastern Massa- chusetts. The Upper Cambrian is known in southeastern Newfoundland, Cape Breton Island, New Brunswick
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