228 



ROLLIN T. CHAM BERLIN 



the trends of the different folds as nearly at right angles as possible. 

 This curvature was necessitated by the fact that the individual 

 ranges are not parallel to one another, but converge toward the 

 south. The curved section crossing these ranges at right angles, 

 and hence also normal to the axial lines of the folds, has its convex 



Fig. 7. — Granby sheet (No. 5) on the right and Sulphur Springs sheet (No. 6) 

 on the left. The Middle Park (early Tertiary) beds occupy a part of the structural 

 basin between Windy Gap and Sulphur Springs while the Uinta beds appear in the 

 lesser basin in the middle of the Granby sheet. 



Fig. 8. — Troublesome sheet (No. 7) on the east and Gore Range sheet (No. 8) 

 on the west. The formations are : (i) pre-Cambrian granite; (6) Red Beds; (7) Mor- 

 rison; (8) Dakota; (9) and (10) Colorado and Pierre; (11) Fox Hills and Laramie,. 

 Basin of Uinta beds in the middle of the Troublesome sheet. The peneplain rests 

 upon the broad crest of the Gore Range. 



side therefore facing northwest. The total length of the section 

 measured on this slight curve is 135 miles. 



The topographic sheets of the United States Geological Survey 

 as yet cover only the eastern portion of this selected section. Here 

 the Niwot, Boulder, and Long's Peak sheets were a great help in loca- 

 ting the field observations and in plotting the cross-section. West of 



