76 



WILLIAM H. HOBBS 



it became standard doctrine throughout Switzerland. From Alpine 

 countries outside Switzerland there have come examples of promi- 

 nent structural geologists long identified with Alpine studies who 

 first fought and later defended the Bertrand-Schardt conception 

 of Alpine structure. 



If a personal incident may be permitted, the writer's own 

 experience has not been greatly different. In the summer of 

 191 2 he entered the central Alps with the paper of WilHs' in hand, 



Kord 



Spaer Amdener Mulde Walensee Miirtscbenstock 



Spitzmeilen 



Vorder-Rlieintal 



A. „Glarner-Doppelfalte" 1870 bis 1902 Escher. iiud Heim. 



B. „Glarner-DeckfaUen" 1833 Berteand, 1892 Suess, 1903 Heim. 



711 = Molasse (Nagelfluli, mitteltertiar) 

 c = Flysch (alttertiar) 



t = helvetisclie Trias (Rothidolomit) 

 V = Vemicano (Sernifit). 



Fig. I. — The Glarus folds and thrusts upon (A ) Escher's conception of the double 

 fold, and (B) Bertrand's view of overfolding and overthrusting (after Heim). 



much impressed by the simplicity and the ingenuity of its concep- 

 tion; but after devoting the greater part of the season to examina- 

 tion of critical districts and to a study of sections across the central 

 Alps, he became convinced of its insufficiency and of the general 

 correctness of the now accepted Swiss view. There can be little 

 doubt that this view is steadily gaining ground among those 

 structural geologists who have given their attention to the subject. 

 Necessity for considering the mechanics oj formation of arcuate 

 mountains. — Though it be true that the theory of "overfolding and 



'Bailey Willis, "Report on an Investigation of the Geological Structure of the 

 Alps," Sniithson. Misc. Coll., LVI, No. 31 (1912), 1-13. 



