358 CARNEGIE INSTITUTION OF WASHINGTON. 



GEOLOGY. 



Chamberlin, T. C, University of Chicago, Chicago, Illinois. Study of 

 fundamental problems of geolocjij. (For previous reports see Year Books 

 Nos. 2-14.) 



A portion of the year was given to the preparation and pubUcation 

 of a small book on The Origin of the Earth, in which an effort was 

 made to bring together, in a form as well suited to the needs of the 

 general scientific reader as the nature of the subject would permit, 

 the main results of the inquiries set forth in a less connected and more 

 technical way in Year Books Nos. 3-14, together with such accretions 

 as had gathered about these. There were included some notable exten- 

 sion of the details of the planetesimal hypothesis and some new matter 

 relative to the application of the planetesimal view to terrestrial prob- 

 lems. Among these was a fuller statement of the origin and extent of 

 the atmosphere and of the dynamic organization of its outer portion 

 as deducted from the kinetic theory of gases. This embraced deduc- 

 tions relative to the mutual interchanges of atmospheres. 



The most notable addition to matter previously pubhshed related 

 to the juvenile shaping of the earth as deduced from its progressive 

 growth under the conditions of rotation, tidal action, and periodic 

 shrinkage. The progressive shaping of the earth, as thus set forth, 

 carries not only a tentative explanation of the great physiographic 

 features of the earth, but a new view of the mode by which approxi- 

 mate isostatic adjustment is accomplished. The mitiation and the 

 early results of this line of study were reported in Year Book No. 12. 



The book issued also included some notable extension of the apph- 

 cation of previous results to the study of stress-conditions within the 

 earth, with indications of the bearing of these upon the mutations 

 and changes of state of the interior, as also upon igneous extrusion 

 and upon the rigidity of the earth. 



The possible habitat of the earliest life and the specific geologic 

 environment under which the physico-chemical syntheses leading up 

 to organic action found conditions suited to their progressive action 

 were also set forth in a final chapter. 



As the study of the genesis of the earth was undertaken in response 

 to a feeling that there was urgent need for a basis of interpretation 

 of early geologic phenomena more closely in accord with the geologic 

 record than was offered by the theories of genesis then current, and as 

 a tentative basis of this kind seems to have been found in the plane- 

 tesimal hypothesis, and as this hypothesis should go through a pro- 

 longed test of its working qualities before a final judgment is formed, 

 it has seemed best to rest the cosmogonic inquiry at this stage and 

 turn to the new aspects of geologic problems that arise under it. It 

 has, hov/ever, seemed worth while to gather up such incidental cos- 

 mogonic suggestions as have arisen in the course of the inquiry, even 



