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Page:Popular Science Monthly Volume 40.djvu/293

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Association of Official Geologists.—The preliminary steps were taken at Washington during the meetings of the International Geological Congress toward the formation of an official organization of the directors of State and national geological surveys. The more important objects of the projected society are the determination of the proper objects of public geologic work, the improvement and unification of methods, the establishment of the proper relative spheres and functions of national and State surveys, co-operation in works of common interest and the prevention of duplication of work, the elevation of the standard of public geologic work and the sustenance of an appreciation of its value, and the inauguration of surveys by States not having any now, which co-operate with the other State surveys and with the national survey.


Changes in Level of the Atlantic Coast.—The fluctuations in height of the Atlantic lowland coast-lands of the United States were described by Prof. W J McGee in a paper read before the American Association. In the Pleistocene period the land stood between three hundred and eight hundred feet below its present level. Immediately afterward the land rose to from three hundred to six hundred feet above its present height, and the shores of the Atlantic and the Gulf retreated to from one hundred to five hundred miles beyond their present position. Afterward the land gradually sank, and the waters readvanced until the geography was much the same as to-day. Then came another incursion of the ocean and gulf, bringing sea-waters over nearly all the area upon which Washington is built, and over considerable portions of the North and the South. During this period there was deposited a series of loams and brick-clay and bowlder-beds, upon which Washington is located, and which has been named, from the District, the Columbia formation. At the close of the Columbia period the land again rose one hundred or two hundred feet higher than at present, and river channels , were cut from fifty to seventy-five miles beyond the present coast-line. It then began to sink, and this movement is yet in progress.


South American Railroads.—Three of the railroads that start from the Pacific coast of South America and run up the valleys of the Andes, says President Gardner G. Hubbard, in his address to the National Geographic Society, are among the most remarkable roads in the world, ascend to a greater elevation than any others, and reach a height which in Europe and the United States would be above the snow-level. They were intended to reach the gold and silver mines between the Andes and Cordilleras. The first, called the Oroya or Central Railroad, one hundred and eleven miles long, starts from Callao and crosses the Andes at an elevation of nearly fifteen thousand feet. It is intended to extend it to the navigable waters of the Amazon. Three hundred miles southward of this, the second road runs from Mollendo, Peru, by Arequipa to Puno or Lake Titicaca, and thence northward on the plateau four hundred and seven miles to San Rosas, on the route to Cuzco. For a part of the way it runs through a country so destitute of water that the only supply for the engines and stations is by an iron pipe eight inches in diameter and fifty miles long, running from an elevation of seven thousand feet to the sea-coast. Seven or eight hundred miles south of Mollendo a line runs from Valparaiso, in Chili, to Buenos Ayres, eight hundred and seventy miles. It crosses the Andes through a tunnel two miles long, at an elevation of ten thousand five hundred and sixty-eight feet above the sea; after leaving the mountains it runs over the pampas two hundred miles, without a curve or a grade more than three feet above or below the plain, and will soon be completed from ocean to ocean. From Rio Janeiro several roads have been constructed over the mountains west of that city to different parts of Brazil. There are now from six thousand to seven thousand miles of road in operation in the Argentine Republic, five thousand or six thousand in Brazil, and three thousand or four thousand miles in the other states, making a total of about fifteen thousand miles of railroad in operation. The apparently most feasible route for the proposed Pan-American Railroad to run from the Caribbean Sea to the Argentine Republic, and to connect with the others, starts from Cartagena, follows the valley of