146 



GEOLOGICAL SURVEY OF THE TERRITORIES. 



point. In regard to the extent of this great and most interesting late 

 basin very little is known. All the explorations have been, hitherto, of 

 a hurried and superficial character. We believe that the Uinta Moun- 



Fig. 12. 



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•'■ •■■■:. r _. - _ ■■ 



'. -■■"■■■■■ .. '''-..'.' '.• - : 



tains form the southern shore, and that it extends down to the valley 

 of Green Eiver, at least to the entrance of White Eiver, and probably 

 further. Professor Denton's graphic description satisfies us that the 

 formations are identical with those around Church Buttes : 



Looking from the summit of a high ridge on the east, a tract of country containing 

 five or six hundred square miles is distinctly visible. Over the Whole surface is rock, 

 bare rock cut into ravines, canons, gorges, and valleys, in magnificent relief — terrace 

 upon terrace, pyramid beyond pyramid, rising to mountain heights ; amphitheaters 

 that would hold a million spectators ; walls, pillars, towers, castles everywhere. It 

 looks like some ruined city of the gods, blasted, bare, desolate, but grand, "beyond a 

 mortal's telling." Originally an elevated country, composed of a number of soft beds 

 of sandstone of varying thickness and softness, underlaid by immense beds of shale, 

 it has been worn down and cut out by rills, creeks, and streams, leaving this strange, 

 weird country to be the wonder of all generations. 



But we must not leave this singularly interesting region without a 

 word in regard to the "moss agates" which cover the country from 

 Green Biver to Fort Bridger in the greatest profusion. The ground in 

 many places seems to be literally paved with nicely-rounded pebbles 

 and small boulders, mostly of agate flint, the largest not more than four 

 or five inches in diameter; there is a belt of about ten miles in width, 

 from east to west, including Church Buttes, and extending an unknown 

 distance, from north to south, over which these gems are found in the 

 greatest abundance and variety. I am inclined to think they originate 

 in this modern tertiary formation. About six miles west of Carter's 

 Station a cut in the railroad reveals a bed of tough, dark-gray, plastic 

 clays, and at the top a layer of flinty concretions filled with small seams 

 of chalcedony. In the "bad lands" of White Biver are abundant 

 seams of fine chalcedony, which only need the oxide of iron or manga- 

 nese to make the choicest of moss agates. I am inclined to believe that 

 these agates originate in irregular seams in the tertiary beds somewhere 

 south of Church Buttes. The origin of all the drift material which 

 strikes the eye everywhere I regard as local, and that it was probably , 

 transported from the direction of the Uinta Mountains. 



