SOME MODERN ASPECTS OF GEOLOGY. 643 



trials, resulting only in disappointment, the students of rocks fol- 

 lowed the example of the theologians ; and, in lieu of observations 

 and facts, produced only the useless and often virulent polemics 

 of the Neptunist and Vulcanist. 



Again, there was a reaction against such waste of energy. 

 Geologists, wearied by more barren controversy, turned eagerly 

 to some new field where observation should be less difficult. 

 They had opened the great book of Nature and had first tried 

 to read the text; but the hieroglyphics were obscure, and the 

 clew could not be found. Is it strange, therefore, that they should 

 have gladly left this hard and unintelligible writing for the 

 picture-book which Nature spread before them in the fossils ? 

 Here at least was something tangible. None now doubted that 

 these fossils had once been living organisms which could be un- 

 derstood by careful comparison with living forms. 



It was through the study of fossil organisms — or paleontology 

 — that geology first accomplished its true aim, viz., the decipher- 

 ing of a portion of the earth's history by observed facts. "We 

 can hardly wonder that a field so fruitful should, since the be- 

 ginning of our century, have been cultivated to the exclusion 

 of almost every other. But paleontology is essentially a biologi- 

 cal, not a geological science. Its service to the sum of human 

 knowledge can scarcely be overestimated, for it has done much in 

 establishing the greatest generalization of this or perhaps of any 

 century — the doctrine of evolution. Nevertheless, its contribu- 

 tions must ever be to the history of life on the globe, rather than 

 to the history of the life of the globe. 



So strong has been the growth of the organic side of our sci- 

 ence that a popular idea still prevails that there is no geology 

 aside from stratigraphy and the fossil -bearing rocks. The paleon- 

 tological school is still in the ascendant, but it is no longer with- 

 out a vigorous rival. 



Within recent years there seems to have been infused into 

 almost every domain of physical science a fresh life. Through 

 gradually acquired generalizations higher points of view have 

 been reached ; old notions have been discarded for newer and 

 broader ones. Prof. Langley tells us of the " new astronomy " ; 

 the doctrine of the conservation of energy has given us a new 

 physics ; evolution, a new biology ; and the study of carbon com- 

 pounds, a new chemistry. So, too, the application of the micro- 

 scope to the study of rocks has given us a new geology. 



The recent development in the science of the earth consists of 

 the return to the work begun by its earliest pioneers. The old 

 Petrographers were right. If we would know the life-history of 

 our planet, we must learn the origin, structural relations, and 

 composition of our rocks. We must discover the forces — chemi- 



