LABORS OF ICE- BORN TORRENTS, ETC. 223 



Fig. 82. Eiver issuing from a Swiss Glacier. 



epoch of thaw and floods, the power of the waters was suf- 

 ficient to move pebbles of the size of a pigeon's egg. I 

 have observed in Middle and Southern Alabama multi- 

 tudes of quartzose and other hard pebbles that could not 

 have been derived from any source nearer than the spurs 

 of the Appalachian ridges in the northern portion of the 

 state. One noteworthy locality is along the gorge of the 

 Black Warrior River, at Tuscaloosa, where Sir Charles 

 Lyell, when on his second tour through the United States, 

 mistook them for the " shingle" of the Cretaceous system. 

 This system produces no such pebbles in Alabama. An- 

 other locality worthy of mention is at Jackson, on the 

 Tombigbee River, in the southern part of the state, where 

 they constitute a bank a hundred feet in depth. In short, 

 these pebbles may be traced all the way to the Gulf of 

 Mexico ; but their normal position is always in the deeper 

 portions of the superficial accumulations. When the pow- 



