in the Erratic Basin of the Khune. 267 



ley, their expansion, and gradual, but always incomplete mix- 

 ture, in the lower part where the glacier spreads itself; all 

 these phenomena, so distinctly marked on the surface of every 

 one of our existing glaciers, are precisely those presented, 

 though on a gigantic scale, by the surface of the erratic basin 

 of the Rhone. Let us imagine for a moment, the existence 

 of this vast glacier of the Rhone, and let us take it at the in- 

 stant, when, in consequence of its progression, it has carried 

 the rocks of the Alps to the extreme limit wliere we now 

 find them, and let us observe what would be the distribution 

 of the superficial moraines which we find on the surface, ac- 

 coi'ding to the acknowledged laws of the mechanism of 

 glaciers. 



In a primeval era, that of its greatest extension, all the 

 space comprised in the acute angle formed on the .south-west 

 by the union of the Alps and Jura, is encumbered with masses 

 of ice, fed by the valleys of the Isere, the Arve, the Dranse, 

 and the Rhone. The outlets are insufficient ; escape by this 

 side is almost impossible, at least for the ice of the valley of 

 the Rhone. A divergency, therefore, takes place by the north- 

 west, where the plain opens and becomes broaderbv the gra- 

 dual retirement of the two chains. The principal mass of 

 the glacier rests upon the Jura, which throws it back towards 

 the plain, in which the ice spreads itself more at ease, and 

 seems even to recoil slightly towards the Alps. Here it meets 

 Avith a new obstacle, the glacier issuing from the valley of the 

 Aar, which presses against the glacier of the Rhone, and com- 

 presses it, without otherwise ai'resting its progress. Lastly, 

 the ices of the Valais, diminishing more and more, at leno-th 

 terminate not far from Aarwangen and Zofingen. Such, then . 

 is the prodigious glacier of the Rhone. 



The moraines distinguishable on this glacier are, 1*/, The 

 right lateral moraine, composed almost exclusively of numer- 

 ous blocks of Valorsine pudding-stone, detached from their 

 principal site on the declivities of the Dentde Morcles ; they 

 extend along the Alps from Fribourg as far as Singine. 2(f, 

 The moraine of Ilaut Valais, charactei-iscd by the white gra- 

 nites, from the southern declivity of the Bernese Oberland 

 and the Galenstock. 2x1, The moraine of Mont Rosa, with 



