266 Wisconsin Academy of Sciences^ Aris,and Letters. 



ing from beneath, instead of casting it over its extremity in the 

 usual method. 



11. The south side of the Ehone also presents a fine exhibit of 

 flaviatile silt, sand and gravel flats, and shows the preeminent 

 tendency of glacial streams to wander widely, back and forth, 

 across their valleys, when the slope is moderate, owing to the un- 

 usual rapidity with which they fill up their channels by the large 

 burden of glacial mud, sand and gravel that they carry, or roll 

 along their beds. They thus rapidly accumulate broad stratified 

 sheets. I suspect that some deposits formed in this way during 

 the Quaternary age have been mistaken for lacustrine formations, 

 owing to their breadth and extent. 



12. None of the other glaciers visited terminate in a manner 

 equally favorable to the observations sought^ but some of them 

 present particular features of equal interest. The terminal mo- 

 raines of the Grindenwald glaciers are even more instructive by 

 way of comparison with oar drift moraines, because of the closer 

 proximity of the successive ridges, and greater similarity of the 

 material, it being a limestone bowlder clay, with some metamor- 

 phic erratics included, and some assorted detritus. Some of the 

 moraine ridges are a pronounced bowlder clay, while others are 

 largely composed of bowlders or gravel. On the inner moraine 

 of the upper Grindenwald glacier, there is much fine gravel and 

 sand in heaps and miniature ridges, presenting a very interesting 

 phenomenon. The outer range is more massive than those of the 

 Ehone glacier, and is very strikingly similar to the Wisconsin 

 Kettle moraine in its superficial expression. The corresponding 

 moraines of the lower Grindelwald glacier show the same features 

 very neatly, and those of the Bois and other glaciers display like 

 characteristics. 



13. So far as my observations went, the nature of the rock over 

 which the glaciers passed was more influential in determining the 

 proportion of clay, sand, gravel and bowlders, than I had sup- 

 posed. Where the rock was mainly granitic, the amount of clay 

 was proportionately small, the detritus being mainly coarse sand, 

 gravel and bowlders. This was doubtless due to the difficulty of 

 reducing the hard constituents of granite to powder. Where the 



