The Appalachian Region: Paleozoic Appalachia, Or, The History of Maryland During Paleozoic Time

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John Hopkins Press, 1900 - Geology - 93 pages
 

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Page 80 - ... other depth. As this statement is true for each layer of the earth's crust, at the surface and below it, it follows that the pressure due solely to weight increases from the surface downward; and as the attraction of gravity also increases in the same direction to a certain depth, the growth of this pressure is more than proportional to the depth below the surface. It is not necessary here to enter into the mathematical discussion of the relations of gravity, density and pressure, but the following...
Page 65 - AND VOLUME OF SEDIMENTS. Succeeding the black Hamilton shales from New York to southern Virginia occurs a great volume of sandy shale and argillaceous sandstone comprising the Jennings and Hampshire formations of Maryland or the Chemung and Catskill of New York. It is divisible into several formations according to the composition, color, texture and included fauna of successive beds, but it is a unit in so far as it represents physical conditions of land and sea which were favorable to rapid erosion...
Page 67 - In the Devonian sediments as they are now exposed to view the typical contour or profile of any delta may not be observable, but the stratification is not less significant. The frequent and irregular interbedding of coarse sands, sandy clays and clays ; the crossstratified beds, the ripple-marked and sun-cracked mud surfaces, the channels scoured by transient streams, all prove the abundance of the sediments, the shifting conditions of deposition, the irregularity of currents, the wide expanses of...
Page 36 - The curve shows the relative extents of the continental and oceanic plateans and adjacent slopes. These relations are expressed independently of the distribution of land and sea. rate of accumulation of sediments depends upon the rate of erosion, though indirectly in many instances; but in general it is true that when lands are prevailingly...
Page 67 - Willis, Bailey, Maryland Geol. Surv., vol. 4, p. 63, 1902. of delta building. The frequent and irregular interbedding of coarse sands, sandy clays and clays, the cross-stratified beds, the ripple-marked and suncracked mud surfaces, the channels scoured by transitory streams, all prove the abundance of sediments, the shifting conditions of deposition, the irregularity of currents, the wide expanse of tide-flats and shallow waters and the weakness of the waves.
Page 67 - The unassorted mingling of sandy and clayey particles is a result of rapid deposition at the mouths of muddy streams in opposition to waves which are too, weak to sort and distribute the volume of sediment. This is a condition of delta-building. In the Devonian sediments as they are now exposed to view the typical contour or profile of any delta may not be observable, but the stratification is not less significant. The frequent and irregular interbedding of coarse sands, sandy clays and clays ; the...
Page 19 - PALEOZOIC APPALACHIA OR THE HISTORY OF MARYLAND DURING PALEOZOIC TIME BY BAILEY WILLIS INTRODUCTION. Some rocks consist of materials gathered beneath the sea and are marked by the water whose currents form them. They are laid...
Page 80 - ... flow. These conditions have been realized experimentally by Professor Frank D. Adams of Montreal, by whom marble has been forced to flow; and in the earth's crust the pressures which result from the weight of rocks establish at a moderate depth the confinement necessary for flowing. The following...
Page 36 - ... Cones of Maryland clays from different localities which have been heated to cone 27 (3038 Fahr.) in the Deville furnace 484 LXIX. Fig. 1. — Chesapeake Pottery Works, DF Haynes& Son, Baltimore. 486 Fig. 2.— Maryland Pottery Works, Edwin Bennett Company, Baltimore 486 Finn HE.
Page 93 - I which the record is wanting. The Paleozoic extent of Appalachia eastward into the Atlantic is a mooted question among geologists. The argument takes note chiefly of two sets of facts, the volume of Paleozoic sediments and the depth of the Atlantic basin. The mass of sediments deposited in the interior...

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