Abstract
III.
Coast of Arctic America.— Melville Peninsula.— Amongst the rock specimens brought home by Dr. Rae, Prof. Tennant recognised gneiss, hornblende slate, and similar metamorphic rocks, a portion probably of the granitic and crystalline rocks described by Sir John Richardson as occupying the central and eastern countries of the Hudson's Bay territory, believed by Sir R. Murchison to belong to the Laurentian system. The latter points out that irom the prevalence of a profusion of Upper Silurian corals characteristic of the Niagara and Onondaga limestones (Wenlock or Dudley), the trilobite Encrinurus punctatus, and the shell Pentamerus oblongus, in the rocks lying on the Laurentian, in the north of the Hudson's Bay territory, and the absence of any traces of Lower Silurian rocks or fossils in the whole of the known polar region, that it is in the highest degree probable that the whole of the country north of the Laurentian Mountains was dry land during the deposition of the Lower Silurian. In the area to the south, and in Europe, and even in the Upper Silurian times, the sea, as evidenced by the presence of Pentamerus, was not a deep one, which is borne out by Sir W. Logan's discovery that the Silurian limestones at the head of Lake, Temiscamang include enormous blocks of the sandstone on which they rest.†
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DE RANCE, C. Arctic Geology * . Nature 11, 492–494 (1875). https://doi.org/10.1038/011492a0
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DOI: https://doi.org/10.1038/011492a0