Bulletin of the Department of Geology of the University of California, Volume 1

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The University, 1896
 

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Page 401 - The measurements of gravity appear far more harmonious when the method of reduction postulates isostasy than when it postulates high rigidity. Nearly all the local peculiarities of gravity admit of simple and rational explanation on the theory that the continent as a whole is approximately isostatic, and that the interior plain is almost perfectly isostatic.
Page 104 - The garnet occurs as crystals, mostly imperfectly developed, known locally as "pockets." These crysManuscript received at the office of the Institute Nov. 30, 1942. * Manager. Barton Mines Corporation, North Creek, NY tals vary in size from a fraction of an inch to a foot or more in diameter.
Page 373 - California lies, as is well known, between the two dominant mountain chains of the state, — the Sierra Nevada on the east and the Coast Ranges on the west.
Page 117 - They are, however, of sufficient importance and immediate interest in the judgment of the writer to warrant present publication, notwithstanding the many gaps which could readily be filled by more systematic inquiry. Even with these gaps, the information here given establishes two general facts of no small moment in certain discussions affecting the recent history of the continent. These are : — 1. The uplift or emergence from the sea of the...
Page 398 - Hence we infer that isostasy is competent only on the supposition that it is kept in action by some other cause tending constantly to disturb the equilibrium which would otherwise result. Such a cause is found in secular contraction, and it is not improbable that these two seemingly divergent theories are really supplementary.
Page 242 - Traces of an Ancient Peneplain. — The Coast Ranges of northern California comprise, besides the mountains proper, which, except for isolated peaks, are distant from the ocean, a broad coastal tract which may be said to be devoid of true mountain topography. This tract is clearly a dissected plateau, and impresses itself as such upon the observer very forcibly when viewed from any point not lower than its general level. The plateau is now represented only *This BULLETlN, Vol.
Page 159 - ... definition of the Pleistocene of the west coast as distinct from the Pliocene, will never be formulated upon a purely palaeontological basis. The reason for this is that there has been no distinct break in the continuity of marine conditions throughout the epochs, only a gradual transition of conditions. In this gradual transition there was, however, a reversal of the epeirogenic movement of the coast from a process of depression to a process of uplift. This turning point of the diastrophic pendulum,...
Page 366 - I, incisor, b, right and left superior molar series (twice natural size). Right premolar shown in section (heavy line) a short distance above the triturating surface. genus, it should perhaps be stated that, although the head bones extend backward beyond the molars, no sign of a fourth tooth could be found on either side.
Page 402 - While the new data thus indicate that the law of isostasy does not obtain in the case of single ridges of the size of a large mountain range, they agree with all other systems of gravity measurements in declaring the isostasy of the greater features of relief.
Page 242 - The progressive uplift of this peneplain, with its residual monadnocks, to an elevation for the plain of from 1,600 to 2,100 feet above the sea level, the adjacent mountainous tracts participating in the same movement. 5. The advance in the new geomorphic cycle to a stage of late adolescence or early maturity. 6. A very recent local sag or depression of about...

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