The Geology of North America

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Professor A. C. Ramsay, F.E.S., F.G.S., recently visited this country, and while here made some notes upon the geology of the Canadas, and the north-eastern provinces generally. The chief object of his investigation was to discover the effects of glacial action ; and he plainly showed, in a recent lecture before the Royal Institution in London, that the valleys on each side of the Lauren-tine chain of mountains, have all been cut by ice. The banks of the St. Lawrence near Brockville, and all the Thousand Islands, have been rounded and montonnee by glacial abrasion during tlie period when all this mass of ice was moving southward into what is now the Atlantic Ocean. He observed the seratchings and striations which are so peculiar to rocks and stones that have been abraded by ice, all along the Catskills, and finding that they do not ron down hill, as they would certainly do had these markings been produced by glaciers, but they run north and south, he concludes that they have been produced by icebergs grating along these mountains when the valley of the Hudson was a sea of 4,000 feet deep, and the Catskills formed the coast line. In fact, it seems from the Professor's paper that the whole of America south of the lakes, as far as latitude 40, is covered with glacial drift, consisting of sand, gravel, and' clay with boulders, many of which during the submergence of the country, have been transported several hundreds of miles from their parent Laurentine chain, and all the underlying rock shows the evidence of having been ice-smoothed and striated. It has long been thought by many geologists that great changes had been effected in the physicial geography of the northern part of this continent, by the action of ice, but it has never been so clearly made out before. We have to thank the cold and uncongenial epoch known as the " glacial period," for the rounded smoothness of our scenery, the gentle slopes, and sweet descents, the Thousand Isles and other beauties of our continent. As a contrast, happy and harmonious, to the lover of the picturesque, stand out the rugged rocks and the rough abraded surfaces, which lend an extra charm to the scenery, and render the Catskills a place of such delight. Nature ia ever lovely ; but when we trace the causes of that loveliness, then wonder mingles with admiration, and intellect as well as sensation is brought into play in the appreciation of our Mother Earth.

Scientific American Magazine Vol 13 Issue 45This article was published with the title “The Geology of North America” in Scientific American Magazine Vol. 13 No. 45 (), p. 357
doi:10.1038/scientificamerican07171858-357

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