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. . 694 i G, E, UNT:ERMANN AND B, R, UNTERMANN was accompanied by s011\e faulting, 3, A long period of erosion followed during which the terrain was reduced to a stage of maturity and Mesozoic sediments were exposed, 4, Uplifting and cousiderable faulting occurred near the close of the Eocene as shown by warping and displacement of some of the Eocene forma- tions of surrounding are~s, 5, Then followed another period of erosion during Oligocene and Miocene time, with gradual increasing aridity,' resulting in depo- sition of the Bishop conglomerate or its equivalent (probably Miocene age) and exposing of Algonkian se~iments, As erosion continued, trenching of the earlier surface was produced, 6,] Some subsidence occurred in the eastern part of the Uinta Range, and the ext~nsive Browns Park formation (Pliocene) was deposited, 7, Continued subsidence and faulting of this area formed a graben in which part of the Browns Park was lowered and protected from erosion, Many of the more prominent faults of the ~egion were formed at this time (late Pliocene or early Pleistocene), with some elevation and tilting toward the west in the eastern end of the range. 8, Development of consequent drainage on the unconformable Browns Park resulted in isuperposition of the streams and in stream deflection and piracy, asillustratedj by Lodore and Split Mountain canyons, 9, With con- tinued general uplift dUrlng Pleistocene, entrenching of meanders of the Green 'and Yampa river systems:progressed, establishing the present day stream pattern and forming the deep canyons and other scenic features of Dinosaur National Monument, 8 Wilmot H. Bradley, (jGeo~orphology of the North Flank of the 'Uinta Mountains/, U. S. CeoI. S.'OBY Prof, Paper 185-1 ('936), pp, '7'-79, . " I.