256 T. C. Chamberlin — Jones's Criticism of 



of the same nature as that of glaciers, as interpreted by 

 Chamberlin (VIII, p. 433), and that of " solid rock-now, " 

 as interpreted by Van Hise (VIII, p. 428). In dealing 

 with this question, then, on the lines laid down by its 

 author, we have nothing directly to do with the molten 

 state of the earth. If any indirect effect is inherited from 

 the molten state, it is merely the favorable or unfavorable 

 condition of the solid matter it has left. The practical 

 question of to-day is merely the alternative whether 

 a solid zone formed by congelation from a molten state 

 would be more, or would be less, favorable to yield than 

 a zone formed from minute mixed solid accretion. To me 

 it seems that the accretional mixture offers somewhat the 

 greater susceptibility to yield in glacier or solid-rock- 

 flow fashion, but if someone else would give different 

 values to the respective susceptibilities, it need not put us 

 into "diametrically opposite" camps. So also in the 

 matter of continental warping, Barrell placed the zone 

 at 50 to 500 miles below the surface. It seems to me that 

 such a small direct up-lift — of the wedging type if you 

 please — as the relief of the continents implies, would be 

 as little likely to destroy the iveakness of the zone as an 

 equal warp by lateral crumpling or any other mode of 

 deformation. Neither would seem to me quite fatal to 

 the weakness of the zone. 



The assignment of 'personal attitudes. — The reviewer's 

 sweeping introductory statement gives the impression 

 that R. T. Chamberlin and T. C. Chamberlin are sharp 

 antagonists of the doctrine of an asthenosphere and are 

 about to promulgate a scheme of wedge-dynamics that, if 

 successful, will "of course" be fatal to it. As a matter 

 of fact, E. T. Chamberlin has been accustomed to teach his 

 classes that an asthenosphere, in the sense of a special 

 yield-zone, is at least a possibility. As his special method 

 of investigating mountain diastrophism is designed to 

 show where the yield-zones actually are — so far as 

 implied by the features of shell deformation — and as his 

 studies are no more than fairly begun, he naturally 

 remains merely a hospitable student of the doctrine of an 

 asthenosphere and refrains from propagandism until the 

 evidences of the case return their verdict. I am not now 

 teaching and I have refrained from going into print on 

 this subject. Instead, I have been trying to gather the 



