48 



GUIDEBOOK OF THE WESTERN UNITED STATES. 



manufactured from 



impure gypsum know 



which occurs near the citj. Pressed brick are made from the 

 Benton shale for constructing buildings in the city and elsewhere. 



Bej^ond Laramie is the station Bona. 



The red beds of the Chugwater formation extend as far north of 

 Laramie as Howell, although for most of this distance they are not 



Howell. 



Elevation 7,113 feet. 

 Omalia 580 miles. 



visible, being covered with beds of gravel. 



West 



aramie is a low ridge where the Morrison (see 



mations 



The 



Howell 



they arc covered with surface debris and can not be seen from 



the train. 



miles north of Ho^\ 



ommff 



the traveler passes tlirough deep cuts in the Benton shale,^ 



From 



omms^ 



station the train passes northward over the 

 Niobrara limestone; which, however, near the track is covered with 



beds of sand and gravel. Outcrops of it appear as 

 Wyoming. light-C4)lored bands southwest of the station on both 



Elevation 7,138 feet, 

 ropulation 191.* 



Omaha 584 miles. 



sides of the river. Northwest of this station the 

 road crosses a tliick deposit of marine shale of middle 

 Upper Cretaceous age, but the shale is hero covered 



with the aUuvial deposits of Laramie Valley. 



summer 



fields of gorgeously colored wild flowers. In some places the plain 

 is colored rod with the blossoms of a variety of loco weed, which is 

 poisonous to hoi-ses, and in others large areas are covered wdth the 



of the larkspur. Evenmg primroses are also 



ssoms 



^ Gypsite is finely divided gypsum 

 niixed witli other matter, which does not 

 interfere with its use for cement plaster. 

 It is baked in ovens, its calcium sulphate 

 remaining as a dry powder, which is 

 mixed with water in plastering and then 

 becomes hard. 



^ The Benton formation in Xebraska 

 consists of three members, two of shale 

 and one of limestone, which are recog- 

 nizable as far west as the east slope of the 

 Laramie Mountains. West of the moim- 

 tains the limestone is represented by shale 

 indistinguishable from the other mem- 

 bers. Near the base of the Benton on both 

 sides of the mountains there is a hard 

 i^mdy shale, called the Mowry, which 

 weathers almost white and which con- 

 Higher in 



I 



:aHi, 



the Benton is a sandstone, about 50 feet 



Basin 



to correspond to the Frontier formation of 

 localities farther west. At some places 

 indications of oil have been found in this 

 sandstone. 



In general there is no material differ- 

 ence in the Benton on opposite sides of the 

 Laramie Mountains, either in physical 

 character or in age, so that it is believed 

 that when these beds were formed the 

 Laramie Mountains did not exist and 

 that the sea in which the sediments 

 accumulated extended uninterruptedly 

 over the area now occupied by the 

 mountains. Some differences in nomen- 

 clature result from the fact that two 

 standard geologic sections have come into 

 use — one for the general region east of the 

 mountains and the other for the region 

 west of them. (See p. 41.) The Laramie 

 Basin is in the transition zone between 

 the two regions. 



