MOVEMENT OF ROCK-MASSES. 253 



It is very improbable that the rocky wall of the Glarnisch, 

 6000 feet in height, could have quite imperceptibly slid over the 

 newer Nummulitic deposits which underlie it, or that the 

 tearing away of the Galanda from the chain of the Kurfirsten- 

 Alvier, with which it forms so remarkable a semicircle round 

 the Sernifite mountains of the Canton of Glaris, could have 

 silently taken place, or that the descent from the Glarnisch of 

 the hills which rise from the bottom of the valley of Glaris (the 

 Bergli and Biirgli) could have noiselessly occurred. Formerly 

 these great overturnings of hills were supposed to have taken 

 place too suddenly and too rapidly ; but now the opposite ex- 

 treme is in vogue, and periods of millions of years are required, 

 over which gigantic changes are continued, so as to adapt the 

 movements of nature to what man has experienced and wit- 

 nessed. 



Let it be remembered how minute a portion of geological 

 annals is embraced in the historic period, and how little man 

 has seen of the prodigious revolutions which the earth has gone 

 through. The notion that these processes have always gone on 

 uniformly and without interruption can hardly be correct ; and 

 we rather find that after long periods of repose the grandest 

 changes take place. Thus, after the long time of quiet deve- 

 lopment which characterized the Carboniferous period, came the 

 stormy Permian epoch, which, in a comparatively short time, 

 brought about a complete transformation of the character of 

 nature ; so also we have seen that the grandest transformation 

 in the whole external features of Switzerland was effected in the 

 comparatively short Pliocene period. 



During Miocene times, in consequence of continental depres- 

 sions and elevations, the Swiss low lands were overflowed some- 

 times by the sea and sometimes by fresh water; but these 

 changes were far more superficial than the movement of the 

 Pliocene period, when, by the elevation of the colossal rock- 

 masses, not only was produced the marvellous structure of the 

 Swiss Alps, but such a lateral pressure was exerted even upon 

 the neighbouring Miocene that along its whole margin from the 

 Lake of Constance to Geneva it was piled up, in a zone several 

 miles broad, into hills and mountains which attained an elevation 



