STRUCTURAL DETAILS OF THE CONTACT 



147 



west ; but higher up it turns to a general north-south direction and follows 

 the western slope of the high, sharp ridge (plate 16) separating Fountain 

 creek and Williams canyon. 

 The upper part of this ridge is 

 composed of the Manitou (Sil- 

 urian) limestone, in which the 

 subterranean drainage of past 

 ages has excavated the Grand 

 cavern and cave of the Winds. 

 For the first quarter of a mile 

 along this slope the contact, 

 Avith the normal southeast dip 

 of 10 degrees, is exposed almost 

 continuousl}^, and is almost absolutely plane, showing no appreciable 

 sags, faults, or breaks of any kind, and crossing great dikes of fine gran- 

 ite in the normal coarse granite without deviation, the granite, regard- 



N.E. 



inch = 4 feet. 

 FiuuBE (5. — Faultinq and Shearing of the Contact . 



s.w. 



N.E. 



S.W. 



Figure 1.— Erosion Irregulariti/ of the Contact. Figuke 8.—Residuari/ Hummock of the Granite Surface. 

 Due to spheroidal form in the granite. 



less of its structure, having been worn down to a plane surface. Farther 

 north along this ridge the contact is mostly concealed by slide and talus 



^ +++ ++A ■+ 



i n c h. = 5" I e et . 

 Figure 9. —Irregular Contact broken bi/ a Fault. 



(plate 16), but in the vicinity of the Grand cavern several original ero- 

 sion irregularities of the contact were observed (figures 7, 8, and 9). 



