88 MAN AND THE GLACIAL PERIOD. 



the gorge is so steep that there was little opportunity 

 either for the accumulation of gravel there or for its preser- 

 vation. Still, the transported gravel and boulders charac- 

 teristic of the melting floods pouring forth from a glacier, 

 are found lining the banks of the Lehigh all along the 

 lower portion of its course. In the Susquehanna Kiver 

 we have a better example at Beach Haven, in Luzerne 

 County, where there are very extensive accumulations of 

 gravel resting on the true glacial deposits of the valley, 

 and extending down the river in terraces of regularly 

 diminishing height for many miles, and merging into ter- 

 races of moderate elevation which line the Susquehanna 

 Valley throughout the rest of its course. Above Beach 

 Haven the gravel deposits in the trough of the river valley 

 are more irregular, and betray the modifying influence of 

 the slowly decaying masses of ice which belonged to the 

 enveloping continental glacier. 



Westward from the north fork of the Susquehanna, 

 similar extensive accumulations of gravel occur at the in- 

 tersection of Fishing Creek in Columbia County, Muncy, 

 Loyalsock, Lycoming, and Pine Creeks in Lycoming 

 County, all tributary to the Susquehanna Kiver, and all 

 evidently being channels through which the melting floods 

 of the ice-sheet brought vast quantities of gravel down to 

 the main stream. William sport, on the West Branch of 

 the Susquehanna, is built upon an extensive terrace con- 

 taining much granitic material, brought down from the 

 glaciated region by Lycoming Creek, when it was flooded 

 with the waters melted from the continental ice-sheet 

 which had here surmounted the Alleghanies and invaded 

 the valley of the Susquehanna. 



Analogous deposits of unusual amounts of gravel, oc- 

 curring in streams flowing southward from the glaciated 

 region, occur at Great Valley, Little Valley, and Steam- 

 burg in Cattaraugus County, New York, and at Eussel- 

 burg and Garland in Warren County, Pennsylvania, also 



