PENNSYLVANIA AND DEPOSITS THEREIN. 



55 



New England streams when the winter ice is hfted by a freshet. 

 Ice-dams are formed at each constriction and sharp bend of the 

 valley, and water ponded to considerable depths, leaving gravel and 

 boulders to be removed by the farmers before cultivation can be 

 undertaken. 



Figure i shows the character of the glacial outwash carried over 

 the broad and flat saddle at Dix from the Bald Eagle to the Juniata 

 Valley, and dropped at Tyrone as soon as the carrying current lost 

 its velocity of 40 inches per second. The Juniata Valley was never 

 touched by the glacier. 



Bald Eagle Ponding. 



When the Kansan lobe that moved down the North Branch of 

 Susquehanna River touched the lofty wedge-end, where Bald Eagle 

 and White Deer mountains meet and rise 1,200 feet above the flood 

 plain of the West Branch of that stream, the water of that branch 

 was ponded west of Williamsport, and the lowest point of discharge 

 was the flat saddle at Dix, just above mentioned, into the Juniata 

 Valley. This fixed the surface of ponding at 1,110 feet, and the 

 depth against the glacier near Williamsport at 650 feet. 



The gravels to be considered came from the wasting of that part 



Fig. 2. End of ridge from Antis Gap, near Jersey Shore. 



