176 STRUCTURAL GEOLOGY. 



It will be shown hereafter that pari passu with upheaval, degradation 

 progressed, and with downthrow, sedimentation, and it .is probable that 

 degradation and sedimentation were necessary to upheaval and downthrow. 

 Yet, for certain purposes, it is desirable that displacement be considered in- 

 dependent of the degradation with which in nature it must always be more 

 or less complicated, and hence the stereogram has been constructed. 



BircVs-Eye View. The difference between upheaval and degradation in 

 the region of uplift can be determined by examining the diagrams in Plate II; 

 but to give a more graphic representation of this important fact in the Uinta 

 uplift, the bird's-eye view, Plate IV, has been constructed. 



Other sections, diagrams and stereograms are found in the atlas, to 

 which reference will be made in appropriate place. All of these sections, 

 diagrams and stereograms are constructed on symmetrical scales; that is, 

 vertical and horizontal scales are the same and all agree with the map. 



THE EASTERN PORTION OF THE UINTA MOUNTAINS. 

 DISPLACEMENT. 



The Uinta Mountains have been produced by the degradation of a great 

 upheaved block having its axis in an east and wes't direction. This axis is 

 not a straight line ; in that portion of the range under discussion it makes a 

 great curve to the north; on the western border of the district the axis is 

 found at Leidy's Peak. It runs a little north of Mount Lena, and in Brown's 

 Park it passes about two miles north of Swallow Canon, then it deflects 



southward and is found ag-ain on Vermilion Creek about four miles above 



%. 



its mouth. The total upheaval above the sea level, along its axial line, is 

 about 30,000 feet. The method by which the amount of uplift is ascer- 

 tained is as follows: It is in evidence that the upheaval began at the close 

 of the Point of Rocks period. The thickness of the rocks exposed on both 

 flanks of the uplift below that horizon is a little more than 25,000 feet, and 

 the lowest bed seen is 5,4.00 feet above the level of the sea. The Uinta 

 Sandstone has not been lifted as high at Leidy's Peak as it has at the mouth 

 of the Vermilion by about 2,000 feet, but the Mesozoic groups attenuate from 

 cast to west, in the same distance, something more than 2,000 feet, and 



