THE BUILDING OF THE COLORADO ROCKIES 227 



ward in the general vicinity of the Grand River, runs by the railroad 

 station at Hot Sulphur Springs, passes 2^ miles north of State 

 Bridge, and ^finally crosses the city of Glenwood Springs and the 



Fig. 5. — Lyons sheet (No. i) on the east and St. Vrain sheet (No. 2) on the west. 

 The restored folds include all beds to the top of the Laramie. The principal forma- 

 tions are: (i) pre-Cambrian granite; (5) Fountain and Lyons sandstones; (6) Lykens 

 (red beds); (7) Morrison; (8) Dakota; (9) Benton and Niobrara; (10) Pierre; 

 (11) Fox Hills and Laramie. The layers have been left unshaded throughout a 

 horizontal strip whose base represents a level 5,000 feet above the sea, and whose top 

 is the tilted peneplain surface. The profile of the present land surface is represented 

 by a line which lies for the most part within this unshaded strip. Each sheet repre- 

 sents a horizontal distance of ten miles. 



Fig. 6. — Allen's Park sheet (No. 3) on the east and Continental Divide sheet 

 (No. 4) on the west. The peneplain here reaches its greatest elevation. A few 

 monadnocks rise above the bowed peneplain and today constitute the high peaks of 

 the Front Range. Fig. 6 represents a horizontal distance of twenty miles. 



Grand Hogback to the flat-lying strata of the Uinta Basin, 6| 

 miles southwest of Glenwood Springs (Fig. 4) . 



The trace of this section drawn on the map is not a straight 

 line, for it was purposely given a slight curvature that it might cross 



