Presented by the Glaciers of Switzerland, 349 



sity exactly similar to that of the stones, in order that, from 

 their primitive position, they may advance almost horizon- 

 tally. Besides, it is necessary not only to make the stones fly 

 like an arrow, but vv^e must assign a tortuous path to those 

 situate near the margin of the bed, without, however, making 

 them lose their speed. In order to account for a successive 

 origin, we must necessarily suppose that the valleys are ex- 

 cavated by the effect of currents, in order that the furrows 

 from above could be formed before those of the middle and at 

 the foot of the slopes. 



I confess that the view of the labyrinth which either of 

 these suppositions opens up, alarms me much more than the 

 idea of countries covered with glaciers. 



By admitting, on the contrary, that the polish in question, 

 the furrows and striaa of countries destitute of glaciers, are 

 the produce of glacial action, we only apply the effects of ex- 

 isting glaciers to forms exactly similar to those which the 

 glaciers continue, under our own observation, to give to their 

 walls ; their ice is sufficiently flexible to ply around the con- 

 tours of their bed, and sufficiently compact to press the 

 grooving body constantly against the wall. The action takes 

 place simultaneously over the whole circumference of the 

 glacier, where the gravel or stones are found at its edge, and 

 where it is not separated from the walls of the bed by some 

 void space ; a space, however, which will disappear sooner or 

 later in its turn, and be again filled with ice and stones. 



2o?, It is not rare to find erratic blocks, especially of a cal- 

 careous^nature, but likewise, also, of a granite, having one of 

 the faces (to the extent of a metre square) flat as a table, 

 and rayed with furrows and striae more or less numerous. 

 Tliese flat surfaces are found in blocks which have travelled 

 upwards of fifteen leagues, and the circumstance appears to 

 me incompatible with transportation by currents, as much in 

 theory as in practice, since the blocks of currents never shew 

 us anything similar. 



3flf, In some places, for instance on the western side of the 

 valley of the Rhine, near Oberried (Canton of St Gall), and 

 a league beyond the baths of Pfeffers, in the valley of Ta- 

 mina, we find on the surface of a polished calcareous rock, for 



