STRATIFIED ROCKS. 185 



tilted strata. But it will be observed that it is the laminae, 

 and not the strata, which are inclined. And, moreover, 

 their extreme irregularity is sufficient to distinguish them 

 from true inclined strata. They seem always to be pro- 

 duced by deposit from rapid, shifting, overloaded currents, 

 and are, therefore, common in river-deposits. 



After explaining these apparent exceptions, we come 

 back with still more confidence to the proposition that 

 stratified rocks were originally soft sediments in a hori- 

 zontal position at the bottom of seas, lakes, etc. But we 

 usually find them now in an entirely different condition 

 and position. We indeed find them sometimes soft, jbut 

 more commonly stony ; sometimes, indeed, still horizon- 

 tal, though raised above the sea and in the interior of 

 continents, but more commonly more or less tilted ; some- 

 times, especially in mountain-regions, not only tilted, but 

 folded, crushed, contorted, broken, and dislocated in the 

 most complex manner, so that it is difficult to make out 

 their natural order. Sometimes the contortion is in the 

 lamince, so that it can be seen in a hand-specimen (Fig. 

 96). Sometimes a series of strata are folded together, 



FIG. 9G. Crumpled laminae. (After Geikie.) 



such as may be seen at one view on an exposed cliff (Fig. 

 97). Sometimes the strata composing the crust of the 



