96 THE RELATIONS BETWEEN FAULTS, OPEN JOINTS, 



examples of such crumpled-up beds may be studied 

 on the coast of Kerry, in the neighbourhood of 

 Valentia, but especially in the cliffs bounding the 

 gut north-west of the hill called Knocknadober, 

 where some of the folds are right angles, others 

 inverted acute angles. Strata when folded either 

 regularly or irregularly, under horizontal compression, 

 need have no open fissures, if quite free to slide on 

 each other, as the material in excess in the trough of 

 the synclinal curves would be pressed up on to the 

 anticlinals. In nature, however, the compression is 

 not truly horizontal, the thrust being due to the 

 shrinkage of the interior of the earth, which crushes 

 and breaks up the solid crust, causing not only an 

 horizontal thrust, but also a forcing up of matter 

 from below, so that in many anticlinal curves we 

 'find the oldest rocks forming the highest ground, and 

 in such cases it appears not improbable that the 

 higher beds have slid down the lower ; or rather more 

 correctly, that the lower beds have been slipped up 

 from under the higher. Some seem to deny that such a 

 slipping could take place, or consider that the slips 

 must be so small that they are nearly unobservable, 

 and could not have affected the present features of 

 the earth's surface. They seem, however, to forget 

 that even if the angle of dip was only a few degrees 

 and the slip a few inches in a mile, that in twenty or 

 thirty miles the slip would be considerable. There 



