UNCONFORMITY OF THE SUMMIT OF THE UINTA GKOUP. 145 



two groups of about four degrees, the lower group having the greater incli- 

 nation to the south. 



The following section illustrates the facts observed here : 



1,000 5,000 feet. 



R. Red "Wall Group. L. Lodore Group. V. Uinta Group. 



Fig. 13. Section showing the unconformity between the Lodore and Uinta Groups in Whirlpool 

 Canon. 



At the foot of the Caiioii of Lodore the unconformity is represented by 

 a difference of dip of from 5 to 6 degrees, and the Lodore Group steadily 

 overlaps the upper members of the Uinta Group, cutting off more than 

 2,000 feet of the latter. Here, also, the Uinta Sandstone is protruded into 

 the Lodore shales. These facts are illustrated in the following section : 



5.000 feet. 



R. Red Wall Group. L. Lodore Group. U. Uinta Group. 

 Fig. 14. Section showing the unconformity between the Lodore and Uinta Groups in the Canon 



of Lodore. 



On the northeast side of the 0-wi-yu-kuts Plateau the Lodore Group 

 is" wanting, and the massive limestone at the base of the Red Wall Group 

 rests upon the Uinta Sandstone. In passing from the northwest end of the 

 ridge along the strike of the sandstone to the southeast, the upper beds 

 of the Uinta Sandstone are seen to disappear, having been cut off by erosion 

 before the deposition of the limestone, and there is from one to two thou- 

 sand feet more of the Uinta Sandstone at the former end of the ridge than 

 at the latter. 



This unconformity can also be seen in the cation of Junction Mountain, 

 and it has been observed on the southern side of the Uinta Mountains, west 

 of the district covered by the map, in the canon cut by the tributaries of the 



Uinta River. 

 10 p ci 



