GENERAL GEOGRAPHIC FEATURES 



431 



river except the Bear and Weber rivers, which flow north and west and 

 empty into Great Salt lake. In contrast with the southern slope the 

 strata are upturned at rather steep angles within a short distance of the 

 axis of the fold. The massive bedded Lower Carboniferous limestones 

 form a bold east-west ridge extending for many miles. Figure 2, plate 

 43, shows this ridge where it is cut through by Beaver creek. 



iLk.'J .A- I — ! ' WESTERN END OF THE RANGE 



At the western end the range becomes much narrower, the limbs of the 

 anticline increasing in dip. The Uinta and Wasatch ranges are separated 

 by the depression of Kamas valley and the irregular group of hills formed 

 of intrusive andesite and extrusive andesite and breccia. The highest 

 points in this part of the range average 10,500 feet in height, and the 

 slopes gradually descend from 10,000 feet to 6,500 feet, the elevation of 

 Kamas valley, in a distance of 5 miles. 



EASTERN END OF THE RANGE • 



This portion forms a broad plateau of horizontal or of slightly tilted 

 strata with an average elevation of 9,000 feet. This simple structure 

 changes to a- very complicated one, following in general the course of 

 Green river. Prominent northwest-southeast ridges mark the line of dis- 

 turbance on the north side and sharp folds and dislocations on the south 

 side at varying angles to the general east-west folding. To the east of 

 Green river there is a considerable depressed area covered by Tertiary 

 sediments. 



Landslides and "Eock Streams" 



The phenomena of landslides include variations from the common type 

 of talus slope to blocks of strata displaced en masse by sapping of the 

 underlying rocks. They are of frequent occurrence, especially on the 

 southern slope of the Uinta range. The most striking form of landslide 

 is that described as "rock streams" by Cross and Howe (7)* in the San 

 Juan region of Colorado. Similar phenomena occur near the summit of 

 Ehodes plateau north of the West fork of Duchesne river and on Farm 

 creek. A typical "rock stream" is shown on plate 44. 



The material forming the landslide contains blocks varying in size to 

 10 feet in diameter, derived from the lower part of the Weber quartzite. 

 The slide is probably due to sapping of the underlying limestone in the 

 cliffs, and when the ice melted in the gulches the support was removed 

 and the quartzite strata were detached as a "stream" of rock. The "rock 



• The numbers refer to numbers in tbe list of references at the end of this paper. 



