PartIV.] § CURVATURE, CRUMPLING. 519 
small scale among the curved Silurian rocks shown in Fig. 240, 
occurs on a grand scale among the Alps, where the folds have some- 
times been so squeezed together that, when the tops of the arches 
have been worn away, the strata could scarcely be supposed to have 
been really inverted, save for the evidence as to their true order of 
succession supplied by their included fossils. The extent of this 
compression in the Alps has been already (p. 314) referred to. So 
intense has been the plication, and so great the subsequent denuda- 
tion, that portions of Carboniferous strata appear as if recularly 
interbedded among Jurassic rocks, and indeed could not be separated 
save after a study of their enclosed organic remains. 
A further modification of the folded structure is presented by the 
fan-shaped arrangement (structure en éventail, Facher-Falten) into 
ai 

Fic. 248.—FAn-sHAPED STRUCTURE, CENTRAL ALPS. 
j, Upper Jurassic Limestone ; 7, Brown Jura and Lias; #, Trias; s, Schistose rocks. 
which highly plicated rocks have been thrown. ‘The most familiar 
example is that of Mont Blanc, where the sedimentary strata at high 
angles seem to dip under the crystalline schists (Fig. 243). 










































Fig. 244.—LocaLLy CRUMPLED STRATA NEAR A FAULT, DALQUHARRAN, AYRSHIRE, 
d, Shales; c, Limestone; b, Boulder-clay. 
Crumpling.—In the general plication of a district there are 
usually localities where the pressure has been locally so intensified 
that the strata have been corrugated and crumpled till it becomes 
almost impossible to follow out any particular bed through the 
disturbed ground. On a small scale instances of such extreme 
contortion may now and then be found at faults and landslips, where 
