Page:Popular Science Monthly Volume 11.djvu/508

492 changes. It was soon recognized that transformations, such as are now taking place, with indefinite time, might do all that has been hitherto ascribed to catastrophes. A careful study of the varieties and rates of contemporaneous change seemed to establish the conclusion that such action is sufficient to account for all geological results. Those sudden and tremendous demonstrations of which we have no experience were discredited; catastrophes went out of fashion, and uniformitarianism became the dominant idea in geology.

Mr. King holds that this doctrine has been carried too far. Prof. Thompson and his school have tried to corner the geologists on the question of time, maintaining on physical grounds that they must check their periods and duration, which would necessitate the quickening of the activities, and thus induce a return-movement toward catastrophism. Mr. King does not argue the case from this point, but puts it on the ground of direct geological evidence that rates of action and change, of which the world at present knows nothing, have been in play at former times on the American Continent. The following passages are illustrative of his views:

"I have thus hastily mentioned a few of the most important geological crust-changes in America whose rates are demonstrably catastrophic. Besides surface-changes involving subsidence, upheaval, faulting, and corrugation, all of which may be executed on a scale or at a rate productive of destruction of life, catastrophes may be brought about by sudden, great changes of climate, or by intense Volcanic energy. In the latter field there are obviously no catastrophes of the first order. Geological maps of the globe have progressed far enough to demonstrate that considerable areas are, and always have been, free from actual ejection of volcanic materials. On the contrary, numerous great regions, notably the western third of our own continent, and the shores of the Pacific, were once literally deluged with volcanic fires. An examination of the ejected rock shows that modern eruptions, by which the volcanic cones of the present period are slowly built up from slight overflows piling one upon another, is not the method of the great Miocene and Pliocene volcanic periods. There were then outbursts hundreds of miles in extent, in which the crust yawned, and enormous volumes of lava rolled out, overwhelming neighboring lands. Volcanoes proper are only isolated chimneys, imposing indeed, but insignificant when compared with the gulfs of molten matter which were thrown up in the great massive eruptions. Between the past and present volcanic phenomena there is not only a difference of degree, but of kind. It is easy to read the mild exhibition of existing volcanoes as a uniformitarian operation, namely, the growth of cones by slight accretions; but such reasoning is positively forbidden in the past.

"If poor, puny little Vesuvius could immortalize itself by burying the towns at its feet, if the feeble energy of a Lisbon earthquake could record itself on the gravestones of thousands of men, then the volcanic period in Western America was truly catastrophic.

"Modern vulcanism is but the faint, flickering survival of what was once a worldwide and immense exhibition of telluric energy—one whose distortions and dislocations of the crust, whose deluges of molten stone, emissions of mineral dust, heated waters, and noxious gases, could not have failed to exert destructive effect on the life of considerable portions of the globe. It cannot be explained away upon any theory of slow, gradual action. The simple field facts are ample proof of the intensity and suddenness of tertiary vulcanism.

"Of climatic catastrophes we have the record of at least one. When the theory of a glacial period came to be generally accepted, and the destructive effects of the invasion of even middle latitudes by polar ice were realized, especially when the devastating effects of the floods which were characteristic of the recession of the ice came to be studied, uniformitarianism, pure and simple, received a fatal blow. I am aware that British students believe themselves justified in taking uniformitarian views of the bowlder till, but they have yet to encounter phenomena of the scale of our quaternary exhibitions.

"A most interesting comparison of the character and rate of stream erosion may be obtained by studying, in the Western Cordilleras, the river-work of three distinct periods. The geologist there finds preserved, and wonderfully well exposed: 1. Pliocene Tertiary river-valleys, with their bowlders,