The American Geologist, Band 14Newton Horace Winchell Geological Publishing Company, 1894 Includes section "Review of recent geological literature." |
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altitude AMERICAN GEOLOGIST Archæan Archean Bactrites baseleveling basin beach beds Belvidere Belvidere section Cambrian Carboniferous chalk coal contains creek Cretaceous crystalline deposits depth Devonian Dinichthys drift drumlins east eastern elevation erosion evidence fauna feet formation fossils GABB Geological Survey GEOLOGIST glacial glacier gneiss granite gravel Helderberg hight hill ice-sheet Iowa lake lake Mendota land limestone lower Madison mass Mesozoic miles minerals moraine mountain nearly Neocomian Niagara Niobrara northern Observatory hill observed occur Ontario origin outcrops Paleozoic paper peneplain Peter sandstone plain plates Pleistocene portion preglacial present probably Prof protoconch quartzite region Report ridge river rocks sand sandstone shales shell shore line Silurian sipho slope southwest species specimens stone strata streams structure submergence surface Tertiary Texas thickness tion U. S. Geol uplift upper valley Wisconsin
Beliebte Passagen
Seite 232 - To sum up the faunal history of the Mesozoic alone, we have seen that pari passu with the creation of broad lowlands there was brought on to the stage a remarkable production of reptiles, a characteristic lowland life; and we note that the humble mammalia were excluded from the peneplain or held back in their development, so far as we know them by actual remains, during this condition of affairs until the very highest Cretaceous. At the close of the Mesozoic, the area of the peneplain was uplifted...
Seite 22 - The recent researches of Henry Ste. -Claire Deville and others go far to show that this breaking up of compounds, or dissociation of elements by intense heat, is a principle of .universal application ; so that we may suppose that all the elements which make up the sun or our planet would, when so intensely heated as to be in...
Seite 238 - These mountains trend slightly west of north, and extend about 40 miles with a width of 15 miles, attaining an elevation of 11,178 feet above the sea and 5,000 to 6,000 feet above the prairies at their base. Their structure has been thoroughly studied by Wolff, who finds that they consist of late Cretaceous strata, soft sandstones, nearly horizontal in stratification, intersected by a network of eruptive dikes.
Seite 290 - ... neither ; when all things are vanity and vexation ; and life seems not worth living except to escape the bore of dying. Even purely intellectual progress brings about its revenges. Problems settled in a rough and ready way by rude men, absorbed in action, demand renewed attention and show themselves to be still unread riddles when men have time to think. The beneficent demon, doubt, whose name is Legion and who dwells amongst the tombs of old faiths, enters into mankind and thenceforth refuses...
Seite 153 - The foregoing references selected from the mass of literature appearing between September, 1841, and March, 1894, while incomplete as a bibliography relating to the physical characteristics and foraminiferal origin of American chalk, may yet help to make clear the successive steps whereby geologists have been led from complete skepticism regarding the presence of chalk on this side of the Atlantic to the conviction that considerable portions of the Niobrara beds along the Sioux and Missouri are,...
Seite 154 - Even in the typical, massive, chalky beds that bear no outward traces of mollusk shells of any kind, these same prisms, while greatly diminished in numbers, are by no means uncommon ; and so in any consideration of the constituent elements of the chalk these separated units from the external layer of valves of Inoceramus must be reckoned as no unimportant factor. When the chalk is treated with acid there remains a small amount of insoluble matter consisting of clay, fine grains of sand, a very few...
Seite 153 - Foraminifera, which may be seen with a good pocket magnifier, seem to have been overlooked. A few months later, however, Williston renewed his observations on the chalk of Kansas, and his report of these later investigations contains the statement that "the deposit seems wholly formed of coccoliths, rhabdoliths and Foraminifera, with, perhaps, radiolarians and sponges."* • The foregoing references selected from the mass of literature appearing between September, 1841, and March, 1894. while incomplete...
Seite 238 - ITS feet above the sea, and 5,000 to 6,000 feet above the prairies at their base. Their structure has been thoroughly studied by Wolff', who finds that they consist of late Cretaceous strata, soft sandstones, nearly horizontal in stratification, intersected by a network of eruptive dikes. The more enduring igneous rocks have preserved this range, while an average denudation of not less than one mile in vertical amount reduced all the adjoining region to a baselevel of erosion.
Seite 351 - ... instantly there followed another volley, another evasion, and another peal of laughter echoed back from the dome, I labored hard until dark, and then discovered a new danger in making it my place of rest. I found a great part of the cave to be lined with a shell of stone loosened by the last winter's frost, and ready at all points to fall with crushing force. Going back to the farthest recess of the dormitory arch, I knocked off all the loose stones, propped up my cot on piles of rocks, and composed...
Seite 153 - In thin sections under the microscope the unbroken shells of Foraminifera are very conspicuous. They lie in close proximity to each other, and their inflated chambers, filled with crystals of calcite, sometimes occupy more than onethird the area of the entire field. It is certain that more than one-fourth, and in some instances more than onethird, of the volume of the chalk is composed of foraminiferal shells still practically entire.