Valleys of the Rhine and Rhone. 161 



Neufchatel is a precisely similar phenomenon to those of 

 Monthey ; but they are eighty miles from the seat of Alpine 

 granite, and are described as not less than 2500 feet above 

 the level of the sea, while those of Monthey are only, on a 

 rough calculation, about 1670. The means by which these 

 primitive masses, including the celebrated Pierre-a-Bot, were 

 borne from their original seat and quietly placed on the sur- 

 face of the Jura limestone, has been the subject of much 

 speculation ; and I need not particularly describe the hypo- 

 thesis of Professor Agassiz, to the effect that glaciers passing 

 across hill and valley at an almost inappreciable angle of 

 declension formed the vehicle of their singular progress. It 

 will readily be observed that a simpler hypothesis is now put 

 within our reach, in as far as the sea appears, from alluvial 

 formations in the Simmenthal, to have formerly stood at a 

 height even superior to the Neufchatel blocks, while M. 

 Saussure acquaints us with water-markings on the Saleve 

 mountains of (as it happens) exactly the elevation of these 

 erratics. In short, it seems far from improbable that ice- 

 bergs boating off from the skirts of glaciers, have been the 

 real vehicles for the blocks in this as in the other case. 



It will be observed that my observations do not lead to 

 the advocacy of any exclusive theory. I admit ancient lakes 

 in certain peculiar circumstances, l)ut deny their concern in 

 all the appearances usually attributed to them. I admit 

 most readily the more extensive and voluminous glaciers of 

 ancient times, but suggest that blocks have been carried, and 

 fixed surfaces smoothed, by other means. Perhaps it would 

 be well if, in scientific speculation, we were to keep our eyes 

 more open than they generally are to diversified causes for 

 similar or nearly similar effects. 



On tJie Smoothed Rock Surfaces of the Rorphyritic Hill^ of 

 Hohburg^ near Wurzen. By Professor Naumann. 



The most interesting phenomenon in these hills is indis- 

 putably the occurrence, by no means uncommon, of smoothed 

 VOL. XLVi: NO. xci. — JAN. 1849. L 



