22 D1ENER : GEOLOGICAL STRUCTURE OF CHITICHUN 



be raised if these crags ought not rather to be considered lam* 

 beaux de recouvrement of an origin similar to that of a good number 

 of so-called Klippen in the Western Alps. 



There are several arguments of no slight importance, which seem 

 to be in favour of such a view. 



Like the Alpine lambeaux de recouvrement the Tibetan crags are 

 confined to a synclinal area, and apparently rest on geologically 

 younger strata. I should not, however, like to insist on the latter 

 argument, as I am too well aware of the difficulty of deciding, whether 

 in similar cases one has to do with a real superposition or with out- 

 crops of older rocks. 1 Nor must it be forgotten that some of these 

 Tibetan crags appear to have been perfectly imbedded in the soft 

 Spiti shales of the igneous materials associated with them, and to 

 have been laid bare by subsequent denudation only. A stronger 

 argument in favour of an explanation of the Tibetan crags of the 

 Chitichun area as lambeaux de recouvrement is their structural in- 

 dependence of the Himalayan folds. This peculiar feature of theirs 

 rnio-ht be easily accounted for by the theory advanced by Bertrand, 

 Schardt, Quereau and Lugeon for the explanation of the majority of 

 the so-called Klippen of Switzerland and Savoy. 



Nevertheless I believe that the latter hypothesis must also be 

 dismissed on account of the very grave objections which might be 

 urged against it. The objection against this explanation of the 

 Tibetan crags as lambeaux de recouvrement is two-fold. 



Supposing these crags to be really the relics of an enormous 

 recumbent fold, the mountain range, part of which has been carried 

 across the Himalayan system into the Chitichun area by means of 

 this hypothetical fold, must exist somewhere in the neighbourhood of 

 th^ latter region. But nowhere in Southern Hundes has a large belt 

 of sedimentary strata of the Chitichun development been discovered. 



i Vide the triassic crags of Beausset and Fuveau, considered formerly— and not only by 

 casual observers— as outcrops ; or the controversy, which is still going on between Heim and 

 Vacekon the structural condition of the Verrucanocaps in the Alps of Glarus. 



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