MECHANICS OF FORMATION OF ARCUATE MOUNTAINS 73 



It was Eduard Suess who first clearly demonstrated the deep 

 significance of the plan of arrangement of Asiatic or Euro-Asiatic 

 mountain arcs. The Alps are to be regarded, as Suess has clearly 

 shown, as an extension into Europe of the Asiatic mountain system, 

 which includes also most of the ranges of southern and south- 

 eastern Europe. The name ' ' Asiatic arcuate structure " or " Asiatic 

 structure" is well chosen for the reason that this entire political 

 division of Asia with the single exception of the peninsula of Hin- 

 dustan, but including the entire group of island fringes as far out 

 as the Bonin Islands and the Mariannes, is characterized through- 

 out by the most pronounced of mountain arcs. Generally less 

 typical, the same structure is represented upon the western con- 

 tinent by the sweeping arcs of Alaska, certain northern ranges of 

 the Rocky Mountain system, and the Appalachians and West 

 Indian ranges; while the only marked example upon the African 

 continent is the Atlas range in the northwest. 



In view of this extent and evident importance of the mountain 

 arc, and its typical illustration in the Alps, no structural geologist 

 can afford to remain in ignorance of at least the broad outlines of 

 the Alpine problem. Whatever may be true of some other moun- 

 tain districts that have been studied, here at least the plan as well 

 as the vertical sections must be fully considered in the discussion 

 of the mechanics of the folding process. 



Conditions favorable for tectonic studies of the Alps. — No moun- 

 tain region has excited so much interest in its structural problems 

 as has the Alps. This is in part to be explained by its location 

 in the very heart of Europe easily accessible to the geologists of 

 every European nation, and in part by the scenic and hygienic 

 qualities of the Swiss highland which have made it the playground 

 not only of Europe but of the world as well. Its rugged features 

 have been mapped in much detail and with praiseworthy accuracy, 

 and the cartography of the country is the pride of every enhghtened 

 Swiss. Switzerland has, moreover, produced structural geologists 

 who have ranked high among their fellows, and the complex 

 problems of Alpine tectonics have gradually evolved from the 

 early conception of Escher von der Linth to the brilHant theory of 



