3 92 FRA OMENTS OF SCIENCE. 



many of the ancient moraines, which date from a period 

 when almost all the mountains were covered with ice and 

 snow, and when, consequently, the quantity of moraine- 

 matter derived from the naked crests cannot have been 

 considerable. 



The erosion theory ascribes the formation of Alpine 

 valleys to the agencies here briefly referred to. It invokes 

 nothing but true causes. Its artificers are still there, 

 though, it may be, in diminished strength; and if they are 

 granted sufficient time, it is demonstrable that they are 

 competent to produce the effects ascribed to them. And 

 what does the fracture theory offer in comparison? From 

 no possible application of this theory, pure and simple, 

 can we obtain the slopes and forms of the mountains. 

 Erosion must in the long run be invoked, and its power 

 therefore conceded. The fracture theory infers from the 

 disturbances of the Alps the existence of fissures: and this 

 is a probable inference. But that they were of a magni- 

 tude sufficient to produce the conformation of the Alps, 

 and that they followed, as the Alpine valleys do, the lines 

 of natural drainage of the country, are assumptions which 

 do not appear to me to be justified either by reason or by 

 observation. 



There is a grandeur in the secular integration of small 

 effects implied by the theory of erosion almost superior to 

 that involved in the idea of a cataclysm. Think of the 

 ages which must have been consumed in the execution 

 of this colossal sculpture. The question may, of course, be 

 pushed further. Think of the ages which the molten 

 earth required for its consolidation. But these vaster 

 epochs lack sublimity through our inability to grasp them. 

 They bewilder us, but they fail to make a solemn impres- 

 sion. The genesis of the mountains comes more within 

 the scope of the intellect, and the majesty of the operation 

 is enhanced by our partial ability to conceive it. In the 

 falling of a rock from a mountain-head, in the shoot of an 

 avalanche, in the plunge of a cataract, we often see more 

 impressive illustrations of the power of gravity than in the 

 motions of the stars. When the intellect has to intervene, 

 and calculation is necessary to the building up of the con- 

 ception, the expansion of the feelings ceases to be pro- 

 portional to the magnitude of the phenomena. 



