Page:Popular Science Monthly Volume 36.djvu/288

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The Name Silurian in Geology.—We have received from Prof. Dana the following note in explanation of a change in geological nomenclature recently proposed by him: "The names for the grander divisions of the Palæozoic series below the Devonian used in most of the recently published works on geology are Cambrian, Lower Silurian, and Upper Silurian. Cambrian was proposed by Sedgwick, and Silurian by Murchison, and both names are derived from the names of ancient tribes of Wales. In 1879 Dr. Lapworth proposed to substitute the term Ordovician. a term of like origin, for the Lower Silurian, and its adoption is under discussion. Although not seeing any need of further change, I urged, in my paper before the American Geological Society at Toronto, that the name Silurian, if it is to be restricted, should be used for the Lower Silurian rather than the Upper, on the ground that it was more just to Murchison and better for the science. I further added that for a new name for the Upper Silurian, rather than go again to Wales for one, we should consider the claims of Bohemia, the land where Barrande carried forward his great work on the Silurian and associated rocks, or to the region of New York and Canada, made famous geologically by the Palæozoic labors of Hall, Billings, and others. I stated that the French geologist, De Lapparent, had already used the name Bohemian for the Upper Silurian; and I then remarked that the lower portion of the Upper Silurian was called the Ontario Division in the Reports of 1842 and 1846 of the New York geologists, Profs. Mather and Emmons, and that this suggested the use of the name Ontarian. This would make the names for the three grand divisions referred to the Cambrian, Silurian, and Ontarian.

"James D. Dana."

History in High and Preparatory Schools.—Two opposite demands, according to Mrs. Mary Sheldon Barnes, have to be met in teaching history in the high school; one for the generalities which are the commonplaces of every scholar, the other for fresh and independent study of historic detail from historic sources. As a solution of the difficulty thus raised, the author proposes teaching the general truth through the special fact, and making each pupil judge the special fact for itself in its general aspects. The first step in this direction should be to give the student a little collection of historic data, and extracts from contemporary sources, together with a few questions within his power to answer from these materials. "Then let him go by himself, like Agassiz's famous student with the fish, to see what he can see." The prominent characteristics of the method employed by Prof. I. B. Burgess, of Newport, R. I., for teaching classical history preparatory to college, are, almost exclusive attention to the facts which are essential to the comprehension of Greek and Roman life and its development; the study of primitive facts, such as maps, pictures of Greek and Roman works; speeches and writings of Greeks and Romans; and the use of questions about these facts, which require not the simple repetition of them, but the gathering and comparison of different facts, and the drawing of inferences from them by the pupil himself.

An Unsettled Part of Minnesota.—The report of the Geological and Natural History Survey of Minnesota for 1887 consists most largely of local details, of interest chiefly to the specialist. The work was prosecuted by three parties, two of them operating in the region of the original Huronian and the iron-bearing rocks of northern Michigan and Wisconsin, and the third in the region of Rainy Lake, while briefer surveys were made in other regions. Prof. N. H. Winchell's examination of the original Huronian leads to some important results which have a direct bearing on the classification of the rocks of Minnesota and of the Northwest. Prof. Alexander Winchell describes the Huronian region as traversed from east to west by a low, interrupted swell, called the Giant's Range, and by another series of still higher reliefs called the Mesabi Range—which must, however, be distinguished from another Mesabi Range—but without conspicuous features of mountain relief. As a rule, the surface is rugged and uncultivable. Between Fall Lake and Grand Portage, and north of Grand Marais, the region is "a literal wil-