FIG. 1. Chief Mountain, Montana, from the north fork of Kennedy Creek. Algonkian resting on Cretaceous. (Willis, U. S. G. S.) The NEW GEOLOGY A TEXTBOOK FOR COLLEGES, by GEORGE MCCREADY PRICE Professor of Geology, Union College, College SECOND PACIFIC PRESS PUBLISHING ASSOCIATION MOUNTAIN VIEW, CALIFORNIA PREFACE In various ones of the natural sciences, it has often happened that the theories of one generation have become the dogmatic doctrines of the next. Fortunately, in such sciences as physics, chemistry, and bacteriology, theories are usually shortlived, unless they rest on a solid basis of facts. Fortunately also, the prime postulates at the basis of most of the natural sciences are merely those basic truths of experience and common sense which are capable of being checked up by reality almost at an instant's notice. In geology, however, we have long labored under the handicap of having several wide-sweeping assumptions lying at the very threshold of our investigations; and these assumptions have shown a phenomenal tenacity of life, because they were of such a nature that they could not readily be checked up by either experience or experiment. Such were the theory of the molten interior of the earth, the theory of uniformity, and the theory of a succession of life in a definite order all over the globe. For many decades, these assumptions and their many corollaries have not only pervaded all the literature of the science, but have also strictly limited observers in what they ought to find in their investigations, just as truly as the scholastics of the Middle Ages felt limited always by what the church had defined as truth. Of late years, it is true, the first two of these three primary assumptions, long venerated as dogmas, have been partly shaken off; for the theory of the molten interior of the earth has fallen into disrepute, and instead of a dead level of uniformity, recent geological theory has been verging more and more toward a sort of cyclical catastrophism, periods of uniformity being considered as having alternated with other periods of greatly accelerated geological action. But the strictly definite order of successive groups of plants and animals has imperceptibly passed out of the position of an assumption, and is to-day treated as the most firmly established dogma of the whole science. And few of the modern students of geology have ever given sufficient attention either to the history of this idea or to its logical foundation to realize that this historical outline of the alleged successive forms of life is still only an assumption, and has already become an incredible assumption, in view of certain facts which have come to light in recent years. When a man trained in any other mental discipline takes up a modern geological report of some particular locality, or dips into a discussion of the age of a particular set of beds, he is at once amazed at the easy confidence with which the geologist asserts a knowledge of the geography of the long-vanished age which is under consideration, with just as definite a knowledge of the migrations of the various types of animals, and the exact time (relatively) in the chronology when certain types of life appeared or disappeared. And he begins to ask in his own mind, "How much of this story is actual fact, and how much is merely imagination or hypothesis?" If he perseveres and attains to a more extensive acquaintance with the science as it is taught and written about to-day, he is not likely to have his query answered, but on the contrary, is almost sure to arrive at the conviction, sooner or later, that geology is a very profound subject, and the underlying principles and methods are deep secrets known only to the initiated; all dabblers must be content to take without question the dicta of experts in these matters. The name of the present volume is not meant as a challenge; but it is meant as the designation of a method which the author believes is here employed for the first time in a geological textbook. Whether the author has always succeeded or not, the effort has at least been made to keep facts and theories clear and distinct; and where alternative hypotheses are possible and permissible, these alternatives are openly stated, and the reader is advised to take his choice. True, the author has often felt free to state a line of argument in favor of that hypothesis which he considers the more reasonable. But it is supposed that even the beginner in the science will acquire a better appetite for more of the subject, and will be more mentally alert to discriminate between the true and the false in the way of theories, if he is not always spoon-fed with those theories which in the minds of most teachers of the science have already crystallized into infallible dogmas. In the first part, and, indeed, in all the body of the work, the great problems of the science have been held steadily before the student as problems to be solved, not as questions already settled by all the experts in the science. Only in the concluding section, when all the leading facts are already before him, has the student been asked to decide between the conflicting hypothetical solutions. If such a method should appear like a new thing under the sun, so far as geological textbooks are concerned, this very fact might suggest to the thoughtful person the urgent need of such an attempt at reforming the method of teaching this subject. And the author |