Page:Popular Science Monthly Volume 59.djvu/266

256 the known facts and to discuss them along the lines so successfully followed in reference to Pleistocene glaciation. An important difference in the argument as applied to the two cases lies in the cause assigned for depletion of the atmospheric carbon dioxide. The postulate of an appropriate time relation between Paleozoic land movements and the epoch of glaciation being conservatively assigned a minor position, the storage of carbon as coal is given major rank in accordance with known relations. This process is not attended by the accelerating and reacting influences, which are due to the equivalent of carbon dioxide contained in bicarbonates, and glaciation would, therefore, result only after depletion had continued longer. In this suggestion is found a possible reason for the wide extension of cool climate and the occurrence of glaciation in remarkably low latitudes.

The broad scope of philosophic thought upon which this working hypothesis rests is indicated by the titles of articles which have flowed from Chamberlin's pen in the last four years. Fortifying his own general researches where needed by those of specialists, he, with reason, challenges fundamental and generally accepted views. He gives the geologist and biologist new clues with which to thread the labyrinth of knowledge, and develops important relations between dynamical geology, stratigraphy, climate and evolution.