540 E. BLACKWELDER GEOLOGY OF WASATCH MOUNTAINS, UTAH 



40th Parallel.^® At the west base of the range the Middle Cambrian 

 limestone abuts against the Archean complex a few hundred feet below 

 the base of the Cambrian quartzite. The stratigraphic displacement in 

 the vertical plane therefore amounts to but little over 2,000 feet. From 

 this point the fault-plane was traced eastward several miles, and its 

 course is inferred (although not observable) for a distance of 15 to 20 

 miles. It crosses the two north spurs of Ogden Peak, shifting the out- 

 crops to the west on the south side, and at the east base of the peak cuts 



Algonkian ? 



Pa/eozoic 

 //me sf ones 



Eocene 



Quafennary 



Figure 9. — Sketch Map of Part of Huntsville Basin and adjacent Bear River Plateau 

 Showing field evidence of tlie extension of the Huntsville fault 



the Willard thrust. Thus the outcrop of the low dipping overthrust is 

 shifted westward on the south side a distance of 2% miles. The soft 

 Algonkian slates above the overthrust have offered little resistance to ero- 

 sion, and to this fact is due the low, hilly region immediately east of 

 Ogden Peak. The fault continues under the Pleistocene sediments of the 

 Huntsville basin, and may therefore be named the Huntsville fault. That 

 it continues much farther east, and with increasing displacement, is indi- 

 cated by the relations of the outcrops in the southern continuation of the 



28 U. S. Geological Exploration of the 40th Parallel, vol. ii, pp. 394-395. 



