Procccdiiif/s of the Ohio State Academy of Science 21 



is almost that time since as an undergraduate at Wesleyan Uni- 

 versity it was my privilege and my delight to take my first course 

 in geology under Professor W. X. Rice. 



In carrying out this purpose I limit myself to the geological 

 principles and theories which have come into prominence in the 

 time under consideration. Detailed studies in the field, laboratory 

 or office are interesting and important, and in many cases mean 

 long months or years of the closest kind of work, but, after all, 

 the general principles which are based on them are the important 

 contribution to geology, and it is these which are of the largest 

 interest to the general student. He wishes, for example, to have 

 a correct theory of mountain formation, but does not care for 

 any greater knowledge of the geological detail than is necessary 

 for a clear understanding of the theory. 



I also find myself under two limitations not of my own 

 choosing. The first is the difficulty, the impossibility, indeed, of 

 escaping my American ]3oint of view and prejudices. This is 

 more difficult. "to do in geology than in any other science, because 

 geological progress is more independent in different nations and 

 continents than is progress in the other sciences. And the reason 

 for this greater independence lies in the verv nature of the 

 science. The chemist and physicist, even the zoologist and 

 botanist, unless engaged in systematic studies, are working on the 

 same materials the world over, and are interested in each other's 

 detail. But the material with which the field geologist deals 

 varies widely in difl:'erent countries, and the detailed work of 

 geologists is different for this reason. The peculiar geological 

 history of the Xorth American continent, for example, offers 

 problems to the American geologist in large measure unlike those 

 in any other part of the world. It determines the character of his 

 detailed studies, his geological principles are in considerable part 

 developed from his own field studies, and his geology progresses 

 in semi-independence of the work abroad. Xot wholly so, of 

 course, for the workers in every land are alive to the general re- 

 sults obtained elsewhere. But the inevitable result is that the 

 work of one's countrymen bulks largest in one's everyday 

 thought, and unconsciously emphasizes the relative value he 



