bt. john.] SECTION THROUGH STATION XXVII RIDGE. 389 



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

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

 only obscure exhibitions of similar beds 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 alti- 

 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 em- 

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

 high bench for about a mile, when the steeper slopes are 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 strata 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 caps 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 from the confluence of Salt Eiver to the crest of Station XX VII ridge, 

 a distance of about four miles, shows the stratigraphic 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 Eiver ; dip 

 southward. 



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

 grassy glades ; no rock exposures observed. 



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

 ascent. 



4. Eed shales and red sandstone debris. 



5. Limestone debris. 



6. Drab shales. 



7. Eed shales and red sandstone fragments. 



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

 bench facing the valley two miles distant ; dip 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 54°, X. 65° E. 



11. Eed shales. 



12. Drab, spar-seamed limestone, with some chert. Dip 55°, X. 60° E. 



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

 503, x. 65° E. 



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

 35 feet. 



15. Eed sandstone, 10 feet. 



16. Eed and chocolate-colored shales, 50 feet. 



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

 dish-brown shales. 



18. Xodular limestone. 



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



20. Brick-red shales, 50 yards across. 



21. Dark reddish-brown, beautifully lamiuated and false bedded, hard- 

 ish sandstone, interbedded with heavy layers of reddish-brown con- 



