FOLDS AND FAULTING. 469 



anticlinal arch often appears to have sunk as regards its 

 outer portion, but it is difficult to say whether elevation or 

 depression has been the actual cause. 



An appeal is made by the author that the conclusions 

 should be tested on the basis of ascertained facts, and not 

 on theoretical considerations, which, he maintains, should 

 follow, rather than lead, the interpretation. 



Applying his deductions to a consideration of the Dop- 

 pelfalte (the central citadel of those holding overthrust to be 

 overfold), he maintains that there is no evidence whatever of 

 the existence of northern and southern return foldings, all 

 the strata represented on Heim's figure (see fig. 1) in dotted 

 lines being absent, while the Jurassic appears in the Rhine 

 valley far north of the position of the point of outcrop 

 necessary to support his theory. 



Again, rejecting the theory of the northern middle limb, 

 he argues that far from the Verrucano covering the Loch- 

 seitenkalk (representing the rolled-out Jurassic) at every 

 spot along the thrust plane, there is in reality a series of 

 broken folds of Jurassic and Verrucano strata at various 

 points overlying the thrust plane, and adds that for the 

 existence of the southern limb of the southern saddle there 

 is no evidence whatever. Therefore the supposition that 

 these members were present, but had disappeared through 

 mechanical deformation and erosion, is purely hypothetical, 

 and only advanced to explain stratigraphical relationships. 



This, however, he considers unnecessary, believing that 

 these relationships explain themselves simply ; a highly- 

 folded Eocene synclinal has been folded over from the 

 south, and, from the north, older rock has been thrust over 

 it along a very slightly inclined plane (see fig. 3), and 

 further, that to the south of this synclinal the beds still in 

 normal position have been trough-faulted, giving rise to the 

 broad Rhine valley. 



He is, therefore, of opinion that the hypothesis of double 

 folding, with the squeezing out of the middle limb, is not 

 only unnecessary, but opposed to facts. The appearance 

 of longitudinal and transverse faults in many parts of the 

 country is entirely foreign to the conception of folding 



