. Carnegie Institution of Washington publication. 270 THE CLIMATIC FACTOR AS ILLUSTRATED IN ARID AMERICA. and the marine Cambric is always a sharp one, leading to the inference that the sea of this time transgressed over an old flat land. Under these circumstances, deposition was not continuous, for the geologic section is here broken between the tillite and the Cambric deposits, indicating that the age of the former is rather late Proterozoic than early Paleozoic. From the evidence of the Lower Cambric life, to be presented later, we shall see that the waters of this time, the world over, wer
. Carnegie Institution of Washington publication. 270 THE CLIMATIC FACTOR AS ILLUSTRATED IN ARID AMERICA. and the marine Cambric is always a sharp one, leading to the inference that the sea of this time transgressed over an old flat land. Under these circumstances, deposition was not continuous, for the geologic section is here broken between the tillite and the Cambric deposits, indicating that the age of the former is rather late Proterozoic than early Paleozoic. From the evidence of the Lower Cambric life, to be presented later, we shall see that the waters of this time, the world over, were of tropical or subtropical temperature, conditions not at all in harmony with the supposed glacial climates of earliest Cambric time. (For further detail see pp. 291-93.). Fig. 89.— of Proterozoic The Norwegian occurronee shown by an empty circle on this map ia supposed to be late Proterozoic, but there is doubt as to the exact date. The occurrence in Great Britain and also the occurrences indicated by diagonal lines are undated Proterozoic. Arctic Noncay.—As long ago as 1891, Doctor Reusch described unmistakable tillites in the Gaisa formation in latitude 70° N. along the Varanger Fiord of Arctic Norway. Similar deposits are also known farther east on Kildin Island, and on Kanin Peninsula at Pae (Ramsay, 1910). At first the age of these deposits was thought to be late Paleozoic and even Triassic, but the Swedish geologists now correlate the Gaisa with the Sparagmite formation, one of the members of the Seve series. As the latter is overlain by the Lower Cambric fauna it appears best to refer the Gaisa formation to the top of the Proterozoic series. The tillite occurs at the very base of the Gaisa formation and overlies the ancient and eroded granites. Strahan reinvestigated the area originally studied by Reusch and his description of the geologic phenomena must convince anyone, not only that here are intercalated thin zones of sandstone and tillite in a
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