Page:The National geographic magazine, volume 1.djvu/284

 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 syncline, 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 reënforced, 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 constituting 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







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