390 EEPOKT UNITED STATES GEOLOGICAL SURVEY. 



glomerate, forms a heavy deposit several Imndred yards across, flagging 

 a prominent outlying ridge ; dip 35° to 45°, 'N. 55° E. 



22. Eed and chocolate-colored shales, 50 to 100 yards across. 



23. Drab, fragmentary limestone, forming a heavy bed; dij) 28^, K. 

 45° E. Contains a small Gasteropod, too imperfect for determiaatiou. 



24. Chocolate-colored and red shales, 50 to 100 yards. 



25. Eeddish-brown, laminated sandstone, 40 feet exposed. 



26. Eeddish shales, space 50 yards across. 



27. Eeddish sandstone, similar to bed No. 25, 10 feet exposed. 



28. Chocolate-colored shales, in steep slope, 50 to 100 yards. 



29. Eedish brown and gray, obMquely-lamiaated sandstone, a heavy 

 ledge 25 yards across the exposure, at one place a mile north of Station 

 XXVIII, forming crest of main ridge; dip 20° to 35°, E. 15° S. to E. 

 30° X. This i)robably belongs to the preceding overlying beds 25 and 27, 

 which together make up a thick deposit, includiug the red and choco- 

 late shales 26 and 28. 



30. Chocolate-colored shales, including a layer of hard, bluish-gray, 

 gritty hmestone, with Belenmites densus, and dark-brown sandstone layers. 

 Exposed in slope west side of crest a mile north of Station XXVII, and 

 100 yards or more across. 



31. Heavy ledge of conglomerate and dark, reddish-brown laminated 

 sandstone, 20 feet exposed -, dip 25°, X. 40° E. 



32. Steep debris-covered slope, 300 yards or more across, showing red- 

 dish shales and reddish sandstones, with harder layers of dirty gray 

 sandstone in lower portion of slope, where the dip is southwestward at 

 an angle of 40°. In the lower portion of the slope a thin, dirty, gritty 

 band occurs, which is charged with a pretty little Gryphcea ("?) charac- 

 terized by a few strong radiating plications ; there are, besides, frag- 

 ments of Ostrea strigulecula and Lingula. 



31a. Heavy ledge, made up of gray sandstone, dark conglomerate, 

 and dark, reddish-brown laminated sandstone, arranged the order 

 mentioned, but imperfectly exposed ; dip 35°, S. 45° W. 



30a. Unexposed space. 



29a. Eeddish-brown, laminated, hard sandstone, imperfectly seen. 



28a. Eed shales. 



27a-25a. Eeddish-brown sandstone, obscure exposure. 



24a. Eed shales. 



23a. Fragmentary limestone, 10 to 15 feet exposed, overlaid, by light 

 drab shaly limestone and indurated calcareous shales, apparently form- 

 ing a heavy bed, 100 yards across the exposure. 



22a. Eed shales. 



21a. Heavy ledge dark, reddish-brown sandstone and conglomerate, 

 dip southwestward, the angle of inclination steepening as the ledge 

 passes down into a deep lateral ravine communicating with McCoy 

 Creek Valley. 



Station XXVII ridge extends above three miles in a direction a httle 

 east of south, its summit preserving quite uniform heights 8,800 to 9,000 

 feet above sea-level. The individual peaks all show monoclinal structure, 

 but the mass of the ridge is built upon an anticlinal fold whose axis 

 apparently lies along the west flank as far south as the station, curving 

 in and out in its course, the conglomerate cap, Xo. 31, at the latter i:)oint 

 belonging to the east flank of the uplift, tjje same as at the point where 

 the foregoing section crosses the ridge a mile to the northward, where, 

 however, this stratum appears in the west slope and arching over, as 

 shown in the accompanying diagram. The strata exposed in this fold 

 pertain to the Jurassic, and besides the general interest of this part of 



