BT.JOHN.] SECTION THROUGH STATION XXVII RIDGE. 389 



tliis side of the valley, the foot of which is closely skirted by the river 

 as far as the confluence of Salt River, two and a half miles, in which 

 only obscure exhibitions of similar bed^ are to be detected for the dense 

 forests that prevail in this quarter. To the south of this, the range 

 passes beyond the limits of our district, gradually diminishing in tdti- 

 tude and in transverse dimension, its east side bounded by the broad 

 valley-plain of Salt Eiver. 



In "making the ascent of the front ridge belonging to the block era- 

 braced between McCoy and Tin-Cup Creeks, the way lay across this 

 high bench for about a mile, when the steeper slopes arc reached at an 

 elevation of 700 to 800 feet above the river. Thence the slope is steeper 

 and more broken to the culminating crest, which bears a little west of 

 north and east of south, the strike of the sti-ata wavering along the crest 

 of the main ridge. Hence, in passing from the north to the southward, 

 different beds are found to constitute the protecting cai^s in the high 

 points, on one of which Station XXVII was located at an elevation of 

 3,520 feet above the valley. The following section, extending southwest- 

 ward ^om the confluence of Salt River to the crest of Station XX VII ridge, 

 a distance of about four miles, shows the stratigraiDhic structure of this 

 part of the range. 



Section through Station XXVII ridge. 



1. Dark brownish-red conglomeritic sandstone, evidently a heavy bed 

 outcropping in brow of high bench 500 feet above Snake River ; dip 

 southward. 



2. Long, gentle slope, densely wooded and interspersed with beautifid 

 grassy glades ; no rock exposures observed. 



3. ileddish-brown arenaceous debris, mixed with the soil in steep 

 ascent. 



4. Red shales and red sandstone debris. 



5. Limestone debris. 



6. Drab shales. 



7. Red shales and red sandstone fragments. 



8. Gray, reddish stained sandstone, a heavy bed outcropping in rocky 

 bench facing the vaUey two miles distant ; dij) 36°, S. 55° W. 



9. Gentle ascent, half a mile or so across, with exposures of chocolate- 

 red shales and reddish-gray sandstone. 



10. Dark drab fragmentary limestone, a thickness of 20 feet exposed 

 in rocky ridge, underlaid by dark drab shales including thin layers of 

 limestone. Dip 51°, X. 65° E. 



11. Red shales. 



12. Drab, spar-seamed limestone, with some chert. Dip 55^', X. 00"^ E. 



13. Drab limestone, similar to preceding beds, 20 feet exposed ; dij) 

 50^, X. 650 E. 



14. Drab shales, 10 feet, underlaid by red and chocolate-colored shales, 

 35 feet. 



15. Red sandstone, 10 feet. 



IG. Red and chocolate-colored shales, 50 feet. 



17. Reddish gray and brown sandstone, interbedded with dark red- 

 dish-bro^vn shales. 



18. Xodidar hmestone. 



19. Dark gray laminated Ihndstone, 15 feet exposed; dip 50°, X. 55° E. 



20. Brick-red shales, 50 yards across. 



21. Dark reddish-bro\^^l, beautifully laminated and false bedded, hard- 

 ish sandstone, interbedded with heav^- layers of redtlish-brown con- 



