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National Geogra/pMo Magazine. 



breaching of the slopes opened the softer Devonian rocks beneath 

 and peripheral lowlands were opened on them. The process by 

 which the Juniata departed from its original axial location, J, 

 fig. 22, to a parallel course on the southeastern side of the syn- 

 cline, J, fig. 23, has been described (fig. 18). The subsequent 

 changes are manifest. Some lateral branch of the Juniata, like 

 N, fig. 23, would work its way around the northern end of the 

 Broad Top canoe on the soft underlying rocks and capture the 

 axial stream, C, that came from the depression between Nittany 

 and Kishicoquillas highlands ; thus reenfoi'ced, capture would be 

 made of a radial stream from the west, Tn, the existing Tyrone 

 branch of the Juniata ; in a later stage the other streams of the 

 western side of the basin would be acquired, their divertor con- 

 stituting the Little Juniata of to-day; and the end would be 

 when the original Juniata, A, fig. 22, that once issued from the 

 subordinate synclinal as a large stream, had lost all its western 

 tributaries, and was but a shrunken beheaded remnant of a river, 

 now seen in Aughwick creek, A, fig. 24. In the meantime, the 



Fig. 22. 



Fig. 23. 



Fig. 24. 



former lake basin was fast becoming a synclinal mountain of 

 diminishing perimeter. The only really mysterious courses of 

 the present streams are where the Little Juniata runs in and out 

 of the western border of the Broad Top synclinal, and where the 

 Frankstown (FT) branch of the Juniata maintains its independ- 

 ent gap across Tussey's mountain (Medina), although diverted to 

 the Tyrone or main Juniata (Tn) by Warrior's ridge (Oriskany) 

 just below. At the time of the early predatory growth of the ini- 

 tial divertor, N, its course lay by the very conditions of its growth 



