286 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1925 



fuller application of it. To-day it is essential for geographers to be 

 perfectly familiar with the past history of the earth in order that 

 they may be able to explain the phenomena oi' the present. 



The question may be summed up by saying that geology has be- 

 come a physiological study of the earth as an organism with a life 

 all its o^Yn. We can watch the geographical changes through which 

 the earth has passed, revealed as they are in the nature and distribu- 

 tion of rocks and fossils. We can even discover the dry land — the 

 actual landscape and physiographic relief itself — preserved in a 

 fossil state, and judge from it the climates then prevailing and their 

 distribution in distinct epochs. We can form some idea of the modes 

 of origin and dates of appearance of continents and mountain chains, 

 and other leading features of the relief of the crust. We are learning 

 to read the evidence given by the interactions of igneous and aque- 

 ous rocks as to the nature of the stresses by which the structure of the 

 crust itself has been moulded. There are, it is true, many gaps in our 

 Icnowlcdge, but their ver}^ existence is of value in quickening and 

 directing research in order that our history may become as full as 

 it can possibly be made. Each advance upon the technical side of the 

 subject, the pursuit of detailed zonal stratigraphy, the application of 

 the miscroscope in so many new directions, and the broadening of 

 the area of study, all react sooner or later in improving, refining, 

 and extending our knowledge of earth history. They combine v.ith 

 the evidence of paleontology to convince us that this earth of ours is 

 still young, active, and full of life, and that any process of " running 

 down " is constantly being held by self-acting checks which are put- 

 ting forward to vastly distant ages " all prospect of an end.'" 



Biological sciences. — While astronomy has given us the conception 

 of illimitable space, it has done much to destroy Avhat has been 

 called the anthropomorphic view- of creation. Geology, on the other 

 hand has endowed us with an almost limitless conception of time, but 

 it has done something to rehabilitate tlie importance of man as the 

 higliest i)roduct yet reached in the long history of the earth. 



This it has done in the main through the intense reality that it has 

 given to the conception of evolution. Although several authors, and 

 two in particular, have pointed out that such a conception could not 

 have been formed without the i)ostulates of time and continuity of 

 existence contributed ])y geology, it is hardly realized how much 

 geological labor on the life of the earth, and on life on the earth, as 

 summed up b}'^ Lyell and grouped and presented by him in his great 

 work on " The Principles of Geology." was necessary to give to 

 evolution a concrete and cogent application. The function of this 

 labor could hardly be better indicated than by the position of geology 

 as displayed in I^yell's earlier editions. Tlie modern reader of them 



