TI1E IIISTORY OF GEOLOGY.
Geology ranks as one of the youngest of the sciences. In the latter part of the eighteenth century the discussion was being waged with warmth by Hutton and his followers on the one hand, and Werner and his followers on the other hand, as to whether any but the most recent ig neous rocks were to be ascribed to other than aqueous agencies, as Werner affirmed. Catastro phism was rampant, and articles on that phase of natural philosophy which dealt with the earth history were mainly philosophical polemics de fending some hypothesis. The clergy took a share in the discussions, opposing any theory of earth history which seemed at variance with the then existing dogmas of theology. It had not yet come to be the custom in the natural sci ences to gather facts patiently, weigh them care fully, and endeavor to draw logical conclusions from them. Rather it seems to have been the custom to take such facts as appeared, philoso phize upon them, and defend the conclusions with vigor against all comers and all fact.
James Hutton, in 1785, sounded the first note of the new geology when he said that he saw "no traces of a beginning, no prospect of an end." This generalization, now a foundation stone of the geological structure, was based upon a wide and thoughtful study and upon many carefully gathered facts. In Playfair's Illustrations of the Iluttonian Theory are to be found many of the principles of modern geology. A second great epoch, in the history of geology was the work of William Smith, at the close of the eighteenth century. As has been stated above, his work made possible the division of the geo logical record into ages based upon scientific principles. His work, therefore, stands as the foundation of stratigraphic geology. The work of Hutton and Smith made it possible for others to follow, and quickly facts began to accumulate and conclusions to he drawn which gave to ge ology the right to be considered as a separate science. Sir Charles Lyell, sometimes called the founder of modern geology, gathered these re sults and added to them his own, putting them together as a system in his Principles of Geolo gy, still a geological classic. He vigorously promulgated his system, and was, without doubt. the greatest and• most effective of geological teachers.
In these earliest days of geology as a science Americans had but little share; but before the middle of the century James Hall, James D.
Dana, and others were vigorously at work on the geology of the North American continent. State geological surveys were established in many of the States; Government geological expeditions and surveys were started; and, finally, the pres ent United States Geological Survey was or ganized. Another event of great importance in
the history of geology was the announcement of Agassiz's glacial hypothesis. Prior to his an nouncement floods, and then floods with ice bergs, relies of the earlier days of catastrophic geology, were appealed to in explanation of the phenomena of the drift. Aside from its impor tance for the science of glacial geology, which it originated, Agassiz's doctrine of a glacial period was important as the destroyer of the last rem nant of catastrophism from geological science. Henceforward uniformitarianism was accepted, and, for a while, perhaps too thoroughly accepted and too blindly followed, as a result of Lyell's energetic advocacy. No longer was there any be lief in the performance of geological work in a limited period of time; but moderate uniformity and great lapse of time were firmly established principles. Perhaps to Darwin's doctrine of evolu tion, which Agassiz did not accept, is due the final establishment of the principle of a great lapse of geological time. Be this as it may, the pro mulgation of the doctrine of evolution was an event of great importance to geology, which made advance in certain phases of geology possible. This theory was based in part on paleontolog ical evidence, and geologists took a large share in its establishment. The discussion which fol lowed its announcement resembled in some re spects the discussion on geological philosophy at the end of the preceding century.
Out of the old natural philosophy have come several sciences, and out of each of these have developed several divisions, or subsciences. some of which may be classed as distinct sciences. The field of geology is so large, and its prob lems are so varied, that, as the body of fact gathered by the army of workers has increased, it has become necessary to subdivide; and, as in all sciences, the tendency is ever toward narrow er and narrower specialization. The generation of geologists now passing away could be familiar with the whole field, as their teachers could be naturalists, and theirs natural philosophers. In one sense this is unfortunate, but in others it is for the best, because with specialization the de tails of knowledge are best gathered. Some day a geological Darwin will appear with large enough grasp of the subject to arrange the facts patiently gathered in the various fields, and to see their bearing, on the great and still unsolved problems of geology.