Geological Sketches, Volume 2"The articles collected in this volume ... were originally prepared from notes of extemporaneous lectures, and first appeared in the pages of Atlantic Monthly."--Preface. |
Other editions - View all
Common terms and phrases
accumulated air-bubbles alluded Alps Ammonites ancient animals and plants Arctic Azoic beds belonging Bivalves blue bands bones called Carboniferous period cause changes character chiefly compact ice comparatively condition connected consequence continent Corals course Cretaceous Cretaceous epoch Crinoids crust Crustacea deposits Devonian earth Elie de Beaumont exist extensive facts Fahrenheit feet Fishes fissures formation fossil fragments freezing geological ages geological periods geologist glacier globe gradually granite heat heavals height infiltration investigations island Jura Jurassic Jurassic epoch kind land later Laurentian Hills layers lines living lower Mammalia margins materials melting modern moraines motion mountains Neocomian névé ocean Permian phenomena physical position present pressure region remains represented Reptiles result rocks rocky sand Shells shores side Silurian slope species strata stratified structure successive surface tained temperature Tertiary tion traced transverse Triassic Trilobites Tyndall types upheaval upper valley vegetation whole wood-cut
Popular passages
Page 178 - ... layer of soil between the successive layers of leaves, — a leafy chronology, as it were, by which we read the passage of the years which divided these deposits from each other. Where the leaves have fallen singly on a clayey soil favorable for receiving such impressions, they have...
Page 19 - Along their northern borders, between Canada and the United States, there runs the low line of hills known as the Laurentian Hills. Insignificant in height, nowhere rising more than fifteen hundred or two thousand feet above the level of the sea, these are nevertheless the first mountains that broke the uniform level of the earth's surface and lifted themselves above the waters. Their low stature, as compared with that of other more lofty mountain-ranges, is in accordance with an invariable rule,...
Page 203 - Southern Europe, in England, where the most complete collections have been made from all these deposits ; and there has never been brought to light a single fact leading us to suppose that any intermediate forms have ever existed through which more recent types have been developed out of older ones. For thirty years Geology has been gradually establishing, by evidence the fulness and accuracy of which are truly amazing, the regularity in the sequence of the geological formations...
Page 19 - This is easily understood when we remember that all mountains and mountain-chains are the result of upheavals, and that the violence of the outbreak must have been in proportion to the strength of the resistance. When the crust of the earth was so thin that the heated masses within easily broke through it, they were not thrown to so great a height, and formed comparatively low elevations, such as the Canadian hills or the mountains of Bretagne and Wales.
Page 22 - Mountains meets the plaia of the Mississippi Valley. We may still walk along its ridge and know that we tread upon the ancient granite that first divided the waters into a northern and southern ocean ; and if our imaginations will carry us so far, we may look down toward its base and fancy how the sea washed against this earliest shore of a lifeless world.
Page 204 - Bears, whose remains are found in Europe from its southern promontories to the northernmost limits of Siberia and Scandinavia, and in America from the Southern states to Greenland and the Melville Islands, may indeed be said to have possessed the Earth in those days. But their reign was over. A sudden intense winter, that was also to last for ages, fell upon our globe; it spread over the very countries where these tropical animals had their homes, and so suddenly did it come upon them that they were...
Page 65 - East, — the first links, few and detached, in the great Alleghany chain which now raises its rocky wall from New England to Alabama. In the Ohio hill, the granite did not break through, though the force of the upheaval was such as to rend asunder the Devonian deposits, for we find them lying torn and broken about the base of the hill ; while the Silurian beds, which should underlie them in their natural position, form its centre and summit. This accounts for the great profusion of Silurian organic...
Page 206 - Among them are the Musk-Ox, the Reindeer, the Walrus, the Seal, and many kinds of Shells characteristic of the Arctic regions. The northernmost part of Norway and Sweden is at this day the southern limit of the Reindeer in Europe ; but their fossil remains are found in large quantities in the drift about the neighborhood of Paris, and quite recently they have been traced even to the foot of the Pyrenees, where their presence would, of course, indicate a climate similar to the one now prevailing in...