MEDITERRANEAN OROGEN COMPARED WITH OTHER SYSTEMS 237 



west in the Sierra I^eA'ada Mountains and thrusting to the east in 

 southern Nevada.^ In the Appalachians evidence has seemetl to indicate 

 overturning toward the west only; but Kober reminds ns that the old 

 land Appalachia has been completely submerged, and he believes the 

 eastern half of the Paleozoic orogen has foundered with it. Support of 

 this theory would be furnished by finding along the Atlantic coast rem- 

 nants of structures with overturning to the east: 



Figure 5. — Blockdiagramm eines normalen rersenkten Orogen, dessen Vorland z, T. 



stehen getliebeti ist 



Kober's figure 31, page 166. 



He uses similar argument in the case of the Andes, where dominantly 

 eastward overfolding and thrusting have been reported. An old land- 

 mass to the west has certainly disappeared, and he believes the western 

 limb of a great orogen went down with it, leaving only the eastern border 

 ranges exposed. This explanation calls for selective faulting on a 

 rather large scale, for it demands quite accurate cleaving of an orogenetic 



Japa n 



Figure 6. — Blockdiagramm des japanischeii Orogen 

 Kober's figure 34, page 168. 



zone along its median line throughout the length of a continent. But 

 Kober thinks we should expect various modifications of the t3^pical 

 orogen. One foreland may be submerged and one entire system of 



Evidently Kober is not aware of this relationship, and it appears that he does not 

 consider the great discrepancj' in age between the folding in the Sierra Nevada and 

 the Rocky Mountain thrusting. Other erroneous conceptions are evident in his dis- 

 cussion of North American geology. 



