OGDEK CA^OK. 399 



cal habit and well-defined lines of bedding. It is a' hard, compact rock, 

 made up of minute grains of rounded quartz, with a somewhat friable text- 

 ure, weathering like a more modern sandstone. It has a light-gray and 

 flesh-colored tint, which is produced by the ferruginous material which is 

 well disseminated through the beds, and prominent on the strata-planes, a 

 characteristic feature of the Wahsatch Cambrian. Under the microscope, 

 the puartz grains are seen to contain liquid-inclusions and minute slender 

 microlitic forms. Near the upper part of the series are found distinct beds 

 of conglomerate, with smooth and even highly polished pebbles of quartzite 

 and jasper, of varying colors, mostly white. They sometimes reach two or 

 three inches in diameter. In one of these beds, an interesting phenomenon 

 is seen, showing the effect upon the enclosed pebbles of the great pressure 

 to which the quartzite has been exposed. They occur flattened on the 

 broader sides and elongated into almond-shaped bodies, and are frequently 

 distorted and bent into curious forms. In several instances, two or more 

 of the pebbles are so pressed together as to apparently form one mass, one 

 having partially penetrated the other. These flattened pebbles appear to 

 lie with their longer axes arranged in parallel planes. 



Directly overlying the quartzite, with sharply-defined lines, occur 75 

 feet of nearly pure argillaceous shales, thinly laminated, of an exceedingly 

 fine texture, and closely resembling beds from the 8am.e horizon underly- 

 ing the great limestone formation of Ute Peak, at the two forks of Muddy 

 Creek. Aljove these occur about 25 feet of nearly similar shales, but carry- 

 ing more or less calcareous matter, which may be recognized under the 

 microscope in minute crystals of calcite. These beds rapidly pass into the 

 well-defined limestone-beds of the Silurian, which are from 1,200 to 1,500 

 feet in tliickness. The lower beds are dark gray, with occasional bands of 

 nearly black limestone. The limestones are usually fine-grained, and pen- 

 etrated in every direction by thin seams of calcite. The rock is apparently 

 siliceous. An attempt was made several years ago to burn it in kilns, but 

 was abandoned, as the lime proved too impure. Several hundred feet above 

 the base of the formation occurs a well-marked bed of argillaceous shale, 

 about 20 feet in thickness, followed by limestone of a decidedly bluish 

 tinge. This is in turn overlaid by a comparatively thin formation of white 



