day: geophysical research iM'.i 



physics; but the time has now come when geologists are not satis- 

 fied with mere description. They desire to interpret the phenom- 

 ena they see in reference to their causes — in other words, under the 



principles of physics and chemistry This involves 



cooperation between physicists, chemists and geologists." 



In a general way, physics, chemistry and biology have already 

 supplied working hypotheses which have been used by students 

 of geology to help in the examination, classification and mapping 

 of the most conspicuous features of the exposed portion of the 

 earth. The geologist has gone abroad and has studied the dis- 

 tribution of land and water, the mountain ranges, the erosive 

 action of ice and of surface water and the resulting sedimentary 

 deposits, the distribution of volcanic activity and of its products, 

 the igneous rocks; or more in detail he has studied the appearance 

 of fossils in certain strata, and has inferred the sequence of geologic 

 time. The distribution of particular minerals and of ore deposits 

 has been carefully mapped. Regions which offer evidence of 

 extraordinary upheaval thru the exercise of physical forces 

 have been painstakingly examined, and so on thru the great 

 range of geologic activity. In a word, the field has been given 

 a thoro general examination, but the manifold problems which 

 this examination has developed, altho early recognized, and 

 often the subject of philosophical speculation and discussion, still 

 await an opportunity for quantitative study. They are often 

 problems for the laboratory and not for the field, problems for 

 exact measurement rather than for inference, problems for the 

 physicist and chemist rather than for the geologist. This is not 

 a result of oversight, it is a stage in the development of the science, 

 — first the location and classification of the material, then the 

 laboratory study of why and how much. 



Certain indications have led us to believe, for example, that the 

 earth was once completely gaseous and in appearance much like 

 our sun. Indeed, it possibly formed a part of the sun but thru 

 some instability in the system became split off — a great gaseous 

 ball which has cooled to its present condition. The cooling 

 probably went on rapidly at first until a protecting crust formed 

 about the ball, then more and more slowly, until now, when our 



