appears to have entered upon a new cycle as the result of uplift, while that of the latter, _in the area shown on the map_, is still unrejuvenated. Farther down-stream, the valley of Sand Creek shows signs of rejuvenation. It may be noted that a tributary of Amber Creek has good opportunity to capture Sand Creek, for the latter flows about 25 miles before reaching the level of Amber Creek at its junction with Elm Creek. [Illustration: PLATE XIII. Fig. 1. COLORADO. U. S. Geol. Surv. Fig. 2. KANSAS. U. S. Geol. Surv.] [Illustration: PLATE XIV. Fig. 1. PENNSYLVANIA. U. S. Geol. Surv. Fig. 2. CALIFORNIA. U. S. Geol. Surv.] [Illustration: +Fig.+ 154.—Profile of a rejuvenated stream. The Lockatong River (N. J.) to the head of Mud Run.] Should the lower end of a tributary valley fail to be degraded as fast as the valley of the main at the point of junction, the tributary is out of _topographic adjustment_ with its main. Falls or rapids may result. When the lower end of a tributary valley is distinctly above the level of its main, the former is called a _hanging valley_. Hanging valleys developed by stream erosion alone are not common except just after the recession of a falls past the mouth of a tributary. Hanging valleys, as well as the characters and relations illustrated by Figs. 152–154 are criteria of rejuvenation, but they must be applied with discretion. Such profiles, for example, as that shown in Fig. 154 may be developed when the rock of a stream’s bed is unequally resistant, and hanging valleys are generally a result of glaciation (see Chapter V). Rejuvenated streams sometimes inherit certain peculiarities from their aged ancestors. Thus a rejuvenated stream may intrench the meanders possessed by the old stream which preceded (see Fig. 1, Pl. XIV, near Harrisburg, Pa.), and intrenched meanders are one of the marks of rejuvenated streams. They are not uncommon in the Appalachian Mountain regions, and are known in other parts of the world. The Seine and the Moselle furnish further illustrations.[59] The history of the new cycle of erosion inaugurated by the uplift would differ from that of the preceding cycle in that the new one would begin with a drainage system already developed. Other things being equal, therefore, the reduction of the land would proceed more rapidly in a subsequent cycle than in the first.