VOLUME XXIx NUMBER 5 
THE 
BeORNAL OF GEOLOGY 
JULY-AUGUST sr921 
DIASTROPHISM AND THE FORMATIVE PROCESSES 
XIV. GROUNDWORK FOR THE STUDY OF MEGADIASTROPHISM 
PART I. SUMMARY STATEMENT OF THE GROUNDWORK 
ALREADY LAID: 
THOMAS C. CHAMBERLIN 
Research Associate, Carnegie Institution of Washington 
PART If. THE INTIMATIONS OF SHELL DEFORMATION 
ROLLIN T. CHAMBERLIN é 
The University of Chicago 
PART I. SUMMARY STATEMENT OF THE GROUNDWORK 
ALREADY LAID 
INTRODUCTION 
As set forth in the first of this series of articles, it has been 
their main purpose to develop into more explicit form the basal 
ideas that logically belong to an earth built up of planetesimals. 
Inevitably, the alternative ideas that have been based on the older 
concept of an earth of gaseo-molten origin have been more or less 
constantly compared with them. The whole of the field has not 
yet been covered, but as the study now passes to a new and 
difficult phase, it is felt that it will be serviceable to assemble in 
brief, rather categorical statements such of the basal ideas already 
« Published by permission of the Carnegie Institution of Washington. 
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