FOLDS AND FAULTING. 457 



must already have existed at an early period, even at the 

 end of Liassic times. 



The importance of these questions, in so far as they 

 bear upon the existence of a distinct crystalline massif in 

 Eocene times, will be obvious. 



The main conclusion he deduces is, that from the 

 Jurassic times onwards the submarine inequalities were 

 already distributed in directions parallel to those of the 

 existing chains, and that the direction of the folds had 

 already been determined at the close of the Liassic period. 



Whilst in Heim's work attention is more especially 

 called to mountain folding as a whole, in this work now 

 under consideration the effects of pressure on strata of 

 different consistency are more immediately considered. 



In the Pays d'Enhaut the conditions are particularly 

 favourable for this purpose, a great mass of Jurassic and 

 Cretaceous limestones being enclosed between Liassic marls 

 and Eocene shales, and an examination of the pre-Alpine 

 range reveals the fact that not merely has there been a fold- 

 ing of the whole, but also a differentiation of movement as 

 regards rocks of varying composition. The Eocene beds 

 appear to have been compressed against the Jurassic lime- 

 stone strata, and as a result the former are not only vertical, 

 but even bent back at the point of junction, the older and 

 harder beds being thrust over the younger series. 



M. Lory having in his work (11) expressed his opinion 

 that faults preceded folds, M. Schardt re-examined the evi- 

 dence, but arrived at conclusions of a diametrically opposite 

 character. He found faults to be in the closest union with 

 foldings, and that not infrequently faults and arches alter- 

 nately replace each other ; that simple vertical faults are 

 purely superficial, never attaining any great depth, and that 

 now dislocated overfolds are rare, owing to the great move- 

 ment which the pre-Alps have undergone. Faulting is mainly 

 represented by true, or, it may be, anticlinal overt hrust, the 

 one limb of an arch being thrust over the other, the throw 

 in some cases exceeding a thousand metres. He says : "It 

 seems certain that the overthrust of the Gastlosen chain, 

 extending as far as the Laitmaire, is formed from a pre- 



