Geological Magazine, Volume 7; Volume 37Henry Woodward Cambridge University Press, 1900 |
Contents
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Common terms and phrases
appears augite Bala Bala Lake beds borolanite Boulder-clay British Museum carapace Carboniferous character clay Coll contains Cretaceous D'Orb deposits described Devonian district Drepanaspis dykes E. A. Smith earthquake east Egypt Eocene evidence fault fauna feet above sea felspar Foraminifera formation fossils fragments genera genus Geol Geological Society Geological Survey geologists Gharib lighthouse groove igneous Island Issel Jebel Abyad Kosseir lake Lamarck later limestone Linnæus Lower margin Megaladapis miles mineral Miocene Mokattam Series nature Nummulites occur ocean Olenus origin orthoclase paper plagioclase plates Pliocene portion posterior present probably Professor pygidium Radiolaria Raibl raised beach Red Sea referred River rocks Salter sand sandstone Schwager shales shell shows side Silurian Sinai sodium species specimens strata structure surface Surv Systema Naturæ Tertiary thickness Tryon tubercles Upper valley volcanic Wadi Gueh Woodward zone
Popular passages
Page 288 - Scientific men get an awkward habit — no, I won't call it that, for it is a valuable habit — of believing nothing unless there is evidence for it ; and they have a way of looking upon belief which is not based upon evidence, not only as illogical, but as immoral.
Page 447 - On a priori grounds there would appear to be no reason why it should not. If two millions of years afforded time enough for the conversion of fish into amphibians, a similar period should suffice for the evolution of trilobites from annelids, or of annelids from trochospheres. The step from gastrulas to trochospheres might be accomplished in another two millions, and two millions more would take us from gastrulas through morulas to protozoa. As things stand, biologists can have nothing to say either...
Page 31 - Dawson, who for ne.irly fifty years has taken an active part in advancing geological knowledge in general, and more especially with regard to the great Dominion of Canada; and they desire to assure Lady Dawson, and the distinguished Fellow of the Society, Dr. George Dawson, of the Council's sincere sympathy in their loss.' The following communications were read : — 1. ' On some Remarkable Calcisponges from the Eocene Strata of Victoria (Australia).
Page 451 - Using the largest number, the area of deposition is found to measure one-tenth the area of denudation; the average rate of deposition will therefore be ten times as great as the rate of denudation, or one two hundred and fortieth foot may be supposed to be uniformly distributed over the area of sedimentation in the course of a year. But the thickness by which we have measured the strata of our geological systems is not an average but a maximum thickness; we have therefore to obtain an estimate of...
Page 558 - American ice-sheet, originating at one time moist oceanic, and at another dry, winds from the land, over the region in question. " It is difficult, however, to restore hypothetically the meteorological conditions of the Pleistocene Epoch, on the theory that the maximum glaciation of the Eastern and Western Continents was contemporaneous. At present the influence of the Gulf Stream and the South.westerly winds indirectly caused by it carries a comparatively warm climate northward during the winter...
Page 443 - Keweenawan .... 50,000 Penokee 14,000 Huronian 18,000 Geologists, impressed with the tardy pace at which sediments appear to be accumulating at the present day, could not contemplate this colossal pile of strata •without feeling that it spoke of an almost inconceivably long lapse of time. They were led to compare its duration with the distances which intervene between the heavenly bodies ; but while some chose the distance of the nearest fixed star as their unit, others were content to measure...
Page 443 - ... time. They were led to compare its duration with the distances which intervene between the heavenly bodies: but while .some chose the distance of the nearest fixed star as their unit, others were content to measure the years in terms of miles from the sun. EVOLUTION OF ORGANISMS. The .stratified rocks were eloquent of time, and not to the geologist alone; they appealed with equal force to the biologist. Accepting Darwin's explanation of the origin of species, the present rate at which form flows...
Page 450 - IN THE ECCENTRICITY OF THE EARTH'S ORBIT. This may perhaps be the place to notice a highly interesting speculation which we owe to Professor Blytt, who has attempted to establish a connection between periods of readjustment of the earth's crust and variations in the eccentricity of the earth's orbit. Without entering into any discussion of Professor Blytt's methods, we may offer a comparison of his results with those that follow from our rough estimate of 1 foot of sediment accumulated in a century.
Page 451 - It is now time to return to tbe task, too long postponed, of discussing the data from which we have been led to conclude that a probable rate at which sediments have accumulated in places where they attain their maximum thickness is one foot per century.
Page 445 - ... splendour had banished the long night that the cheerful sound of running waters was heard again in our midst. Then the work of denudation and deposition seriously recommenced, not to cease till the life of the .sun is spent. Thus the thickness of the stratified series may be a measure rather of the duration of sunlight than of the period which has elapsed since the first formation of the ocean. It may have been so — we cannot tell — but it may be fairly urged that we know less of the origin,...