ANNIVERSARY ADDRESS OF THE PRESIDENT. lui 



a period of rest long enough to allow the waves to leave a pernia- 

 nent record of their action ; and further, that throughout Switzer- 

 land the whole chain was equally elevated, or as nearly so as can be 

 determined by this method of observation. The moves were sup- 

 posed to commence by jumps of 1000 feet or more, but then to 

 become less, and at last scarcely discernible ; the periods of longest 

 rest correspond to the lines of erosion at 9000, 7500, and 4800 feet, 

 and the epochs are supposed to have extended from the termination 

 of the eocene to a period subsequent to the last tertiary de{)osit, 

 nothing but drift having been formed during the last period of 

 elevation. The various valley-terraces Mr. Sharpe supposed to have 

 been formed of detritus heaped up by the sea at the mouths of river 

 openings, or ravines, at each temporary rest, and the correspondence 

 of height of these terraces in different and widely separated valleys 

 with the lines of erosion, he considered a strong proof that at least both 

 were results of some common cause. But, even were this admitted, 

 the preservation of such terraces would appear inconsistent with vio- 

 lent changes of level, as the sudden rise of the land and the drag of 

 the receding waters must have at least disturbed their loose materials, 

 and shattered their mass, so as to destroy that regularity which is now 

 their great characteristic. 



Grand as this speculation is, it requires to be tested by more ex- 

 tended observations. Portions of the secondary as well as of tertiary 

 deposits stretch into the Alpine valleys, so that it is evident that 

 either the present configuration of much of the surface must have 

 existed prior to the most ancient of these deposits, or that the rocky 

 nucleus must have been forced through them subsequently, so as to 

 produce by local disturbances the valleys as they now exist ; the lat- 

 ter being probably most consistent with the disturbed character of 

 much of the strata, — such, for example, as the anthracitic Jurassic 

 beds, which are found resting horizontally on the tops of the Aiguilles 

 Rouges and at the same time in the valley of Chamounix below. 



This indeed is Mr. Sharpe's view, as he states, that at the end of the 

 Eocene period, the elder Nagelfluh, the enormous thickness of which 

 is seen at the Rigi and neighbouring mountains, points out the period 

 of that great elevation, when the central masses of the Alps being 

 thrust upwards for the last time through the crust of the earth, the 

 mountains received their present form, and the secondary rocks on the 

 flanks were thrown into the disturbed position they now occupy, whilst 

 the alternation of freshwater and marine deposits in the Molasse in- 

 dicates pulsations, as it were, in the earth's crust, sometimes pro- 

 ducing elevation and sometimes depression ; but then, in his opi- 

 nion, the whole country sank again at least 9000 feet, and at a later 

 period a new and final elevation commenced, the consequence of 

 which was fresh wear, and the dispersion of gravel and boulders 

 over the low lands of Switzerland. On such an hypothesis, some 

 of the later tertiaries, the fauna of which so nearly resembles that of 

 the existing epoch, become separated from it in time, by the vast 

 period assumed as necessary, first, for the subsidence of the whole 

 country through a space of 9000 feet, and then for its elevation to 



