FOLDS AND FAULTING. 471 



morphosis without faulting, and (4) he strongly insists 

 that many of the principal Swiss valleys are the production 

 not so much of erosion as of faulting. 



In support of these views Dr. Rothpletz, in his latest 

 work, has gathered together evidence from all the principal 

 mountain regions. In the Linththal, opposing the view 

 that folding has originated in the deeper-seated portions of 

 the earth's crust without faulting, he maintains that great 

 dislocation fissures occur which extend downwards into the 

 deepest strata open to observation. 



He also points out that where, according to the Doppel- 

 falte theory, Jurassic Hochgebirgskalk was supposed to exist, 

 in reality, the whole precipice consists of all strata from 

 Eocene to Dogger, and instead of a simple inversion having 

 here taken place (south fold of southern saddle, where the 

 squeezed out middle limb is shown overlaid by Verrucano), 

 the whole is folded into a series of troughs and arches, the 

 Malm being in places folded three times on itself, sometimes 

 enclosing Dogger and sometimes Eocene beds. 



He describes a series of vertical to overturned folds in 

 the Sentis region, cut through by inclined longitudinal 

 fissures, along whose fault planes the upper side has been 

 thrust over the lower. These overthrust planes follow in 

 general the longitudinal direction of the folds, but they are 

 never absolutely parallel with the strike of the strata, being 

 mostly of greater inclination than the latter. 



The overthrusts are clearly younger than the folds, cut- 

 ting sometimes across the highly inclined, and at other times 

 through the horizontally lying fold limbs, having no definite 

 relation which would prove them to have been derived from 

 the overfoldinp- of the same. On the other hand the fault 

 planes are clearly younger than either, and along them hori- 

 zontal displacements and depressions have taken place, 

 giving rise to all the varied mountain forms of the Sentis 

 range. 



In the Juras we again learn on Muhlberg's authority 

 that the folds and overthrusts have not the same strike, and 

 that the latter could not have been sufficient to squeeze out 

 a middle limb 800 metres in thickness (this figure represent- 



