STRATIGRAPHIC CLASSIFICATION DIASTROPHIC CRITERIA 395 



Chaniberlin's views. — Two widely different conceptions of body defor- 

 mation prevail among modern geologists. The important features of 

 these divergent views have been briefly stated by Chamberlin in a paper 

 entitled "Diastrophism as the ultimate basis of correlation.^'^^ As I con- 

 cur in general with the principles advocated therein by this authority, a 

 few sentences quoted from this paper will serve present purposes perhaps 

 better than any I might write. He says : "There remain two conceptions 

 of general or body deformation between which choice must be made. 

 In the one, the deformations are supposed to be indifferent to their pre- 

 decessors and to disregard the configurations produced by previous de- 

 formations. Their successive effects upon continental outlines and basin 

 capacities are thus heterogeneous and the combined results irregular and 

 uncertain. . . . The submergent phase of one continent or fraction 

 of a continent may, in this case, be contemporaneous with the emergent 

 phase of another continent or fraction of a continent, and the progress 

 of events on one continent is as likely to be contrasted with those of an- 

 other continent as to fall in with them coordinately." This conception, 

 entertained chiefly by certain European geologists, is rejected by Cham- 

 berlin on what, especially as regards the indifference of deformations to 

 their predecessors, seem to me valid grounds. The last of the quoted sen- 

 tences seems less objectionable, since, as explained on pages 405 to 409, 

 the conditions mentioned are probable also under the second conception. 



"According to the other view, deformations are inheritances, one of 

 which follows another in due dynamical kinship. The succession is there- 

 fore homogeneous and the results coordinate. If, for example, the first 

 depression of the abysmal basins was due to the superior specific gravity 

 of the basin-bottoms, this specific gravity remained and participated in 

 the next deformation. If the continental masses, at the outset of conti- 

 nental formation, were relatively low in specific gravity, this low specific 

 gravity was handed down to later periods and helped to renew deforma- 

 tion of the same phases in the same regions. Under this view, ocean 

 basins and continental elevations tended toward self-perpetuation. It is 

 not assumed that this prevented shell crumplings, provincial warpings, or 

 Ijlock movements of diverse phases within the continental or the abysmal 

 areas, for these might obviously be necessary effects of the general defor- 

 mative movements, or at least inevitable incidents connected with the 

 dynamics lying back of them. . . . Each great diastrophic movement 

 tended toward the rejuvenation of the continents and toward the firmer 

 establishment of the great basins. . . . The baseleveling processes have 



S3 T. C. Chamberlin : .Journal of Geology, vol. xvil, 1909, pp. 685-693. 



