The founders of geology / by Sir Archibald Geikie.

  • Geikie, Archibald, 1835-1924.
Date:
1897
Catalogue details

Licence: Public Domain Mark

Credit: The founders of geology / by Sir Archibald Geikie. Source: Wellcome Collection.

    82/320 (page 66)
    other in age and other characters. The first of these classes includes the younger lava - streams, not yet cut through by running water, and still connected with their parent cones. The second embraces those lavas which bear decomposed earthy materials on their surface, and from which their original craters have disappeared. In the third class are ranged those lavas which have been reduced to detached outliers separated by valleys; while in the fourth, some isolated masses are placed which Desmarest thought had been “melted in place,” or erupted where they now appear. The third part of the memoir, though read with the second part in 1771, was not published until 1777. In this essay the author discussed the basalt of the ancients, and the natural history of the various kinds of stones to which at different times the term basalt had been applied. It is interesting to follow the slow elaboration of his views through his successive memoirs. We must remember that, during these busy years, Ms time and thoughts were chiefly taken up with the inquiries into industrial develop- ment which the Government of the day had entrusted to him, and wMch necessitated frequent and prolonged journeys, not only in France, but in other countries of Europe. He felt that the great questions in physical geography which specially occupied his attention could best be studied in Auvergne. He returned to that region at every available opportunity, revisiting again and again localities already familiar to him, and testing his deduc- tions by fresh appeals to nature. Four years after his great monograph on the origin of basalt had been read to the Academy of Sciences, he presented another essay.