262 Wisconsin Academy of Sciences^ Arts, and Letters. 



more gentle slope. Here its foot spreads out into a flat semicir- 

 cular form not altogether unlike an equine hoof. 



The first point of special interest to be noticed is that the cre- 

 vasses in this flat portion diverge in curving lines from the axis of 

 the glacier toward the expanded margin. This I believe to be cor- 

 related with a divergent motion of the ice bj which the expanded 

 foot was formed ; and in this I find a close analogy to the diver- 

 gent motion of the ice of our own ancient Grreen Bay glacier, as 

 shown in my recent report. The valley of the Rhone just below 

 this is covered with drift, so that the striations, which it might be 

 presumed to have made in its recently more expanded condition, 

 are concealed, but at the foot of the Glacier de Bois, in the Cha- 

 mouni valley, a divergence in striation amounting to about 75* 

 was observed. 



2. The Ehone glacier is now retreating at a somewhat rapid 

 rate. With commendable regard for the interests of science and 

 the profit of transient students, the successive positions occupied 

 by the retreating foot of the glacier, each year since 1874, have 

 been marked by lines of tarred bowlders and cairns. The method 

 and rate of retreat is thus mapped out on the face of the valley 

 itself. It will be sufficiently near for our purposes to say that 

 the average retreat since 1874, has been about fifty paces per year. 

 It therefore presents a fine opportunity to observe the deposition 

 of a receding glacier, and, as it bears but little detritus on its sur- 

 face, its abandoned ground moraine is well exposed for study. 

 However, certain portions of the plain have been swept by glacial 

 floods, which have somewhat modified the deposit, and care should 

 be taken not to confuse the two deposits. A little close observa- 

 tion will show that in the portions recently abandoned by the 

 glacier, and that have not been washed by the issuing waters, the 

 bowlders frequently bear, perched upon their tops and slopes, 

 sand, pebbles, and small fragments of rock. It is hence evident 

 that they have never been swept by even the gentlest stream, and 

 that no assorting or modifying action of any kind has been 

 brought to bear upon them since they were abandoned by the ice. 

 Purthermore, we may go to the foot of the glacier and see them 

 slowly issuing, thus crowned, directly from the ice. 



