Mesozoic and Camozoic Geology and Palaeontology. 265 



The Brown's Park Group occupies that expansion of Green river 

 valley which is known as Brown's Park. From there it extends east 

 ward and around the eastern end of the Uinta uplift, except a few miles 

 interruption of its continuity there, and thence extends westward 

 along the southern base of the Uinta mountains a large part of the 

 length of tliat range. It extends northward from the eastern portion 

 of the Uinta mountains, as far as Dr^^ mountains and Godiva ridge. 

 Remaining patches of it show that the formation formerly extended 

 eastward as far as the foot hills of the Park range. It occupies nearly 

 the whole surface of the western portion of Axial basin, comparativel}^ 

 small areas immediately east and immediately north of Yampa moun- 

 tain, and a considerable portion of the space between Junction moun- 

 tain and the eastern end of the Uinta uplift, all of which spaces are in 

 unbroken continuity. It, also, occupies a large space from Raven 

 ridge and Red Bluff Wash extending far westward. 



F. M. Endlich observed the Wasatch and Green River Groups 

 spread over an area in the White river region of western Colorado, of 

 more than 3,000 square miles. A section on Douglas creek, a branch 

 of White river, showed a thicknesss of 1,500 feet for the Wasatch 

 Group. A'^stratum of brick-red sandstone, 160 feet in thickness, and 

 placed immediately below the middle of the Group, served as a land- 

 mark for identification. Inferior beds of coal occur in the upper part 

 of the Group. Groups of columnar monuments, and monuments 

 composed of shales with cappings of sandstones are not uncommon. 



Fine exposures of the Green River Group occur ill the Book Cliffs, 

 just north of the Grand river. Geognosticall}' and lithologically 

 speaking, it is separable into an upper and lower division. The lower 

 arenaceous division having a thickness of 2,400 feet, as obtained from 

 the southern bold escarpment of the plateau, and corroborated by 

 observations elsewhere ; and succeeded by laminated shales, having a 

 thickness of 1,000 to 1,200 feet ; the upper division consisting of 

 yellow and brown sandstones, with thin interstrata of dark shales, and 

 having a tliickness of 1,100 to 1,200 feet. These sandstones, by ero- 

 sion and weathering, have assumed many fantastic shapes, some imi- 

 tating the ruins of some ancient building, and others rising in spires 

 for several hundred feet above their gently sloping surroundings. A 

 group of three of these weathered monuments near Asphalt Wash, in 

 White river valley, one of which is 80 feet high, received the name of 

 the '' Happy Famil}'." 



On the AVhite river drainage he observed no evidence pointing to the 



