380 /. C. White — Bowlders at high altitudes. 



Along the South Potomac, the Shenandoah, the James, and 

 other rivers of Virginia, large deposits of rounded bowlders are 

 found far above where the present streams ever rise, and the 

 similarity of the deposits to those occurring along the rivers 

 west of the Alleghenies is very striking. It is barely possible 

 they have had a common cause in a submergence of continental 

 extent, but at the same time there can be no doubt that the 

 hypothetical "Ice Dam " of Prof. Wright, would satisfactorily 

 account for all the phenomena of surface geology which exist 

 along the rivers west from the Alleghenies. 



Submergence, with re-elevation in comparatively recent times, 

 will then give a sufficient explanation for the existence of the 

 elevated bowlder deposits in the vicinity of Washington, D. C, 

 Richmond, Philadelphia, and possibly as far west as Cumber- 

 land, but along some of the Appalachian rivers we meet with a 

 class of facts that neither the " Ice Dam " hypothesis of Prof. 

 Wright, nor the (seemingly demonstrated) Atlantic coast sub- 

 mergence will satisfactorily explain. Reference is here made 

 to the bowlder deposits that occur far above the level of the 

 present streams, when we have followed them so near their 

 sources as to be high above the limits of Prof. Wright's "Ice 

 Dam," and also still higher above any evidence of continental 

 submergence. One of these remarkable deposits may be seen 

 on Cheat River, in Tucker County, West Va., a short distance 

 above St. George. The elevation of the river's bed is there 

 about 1500 feet above tide, and yet great deposits, of rounded 

 bowlders and other detrital material are found lining the valley 

 in terraces up to 175 feet above the level of the stream. It has 

 occurred to me that possibly during the long cold of the Glacial 

 epoch, the snows may have accumulated to a depth sufficiently 

 great along the Alleghenies to form local slides of considerable 

 extent, which might dam up the streams in their upper reaches 

 where they flow along the slopes of the mountains in narrow 

 gorges, like the Cheat in the vicinity of Rowlesburg, a few 

 miles below where the terrace deposits in question have been 

 noted. 



Mr. N. D. Adams, of St. George, and the present editor of 

 the Wheeling Register, informs me that near the county seat of 

 Tucker there is a very high hill bordering the valley of Cheat 

 River, and that circling back around it is an old river channel 

 filled with water-worn stones and other transported trash at a 

 considerable Elevation above the level of the river. This, to- 

 gether with the terrace deposits observed by myself above St. 

 George, would seem to prove that the valley of this stream has 

 been submerged in that region within recent geological time, 

 or at least not earlier than the Glacial epoch, and yet I can see 

 no explanation for the submergence in this or other similar 



