ST.JOHX.] SECTION NORTH OF STATION XXV. 383 



hinted in the northerly inclined strata of similar appearance, which malf o 

 up the barrier on the northeast side of the valley in the quarter here 

 referred to. 



Three miles above Fall Creek, at the point where a little stream de- 

 scends into the valley from the abrupt northern or front spur descending 

 from Station XXV — one of the dominating- points of the eastern front of 

 th(> range between Fall and Pyramid Creeks which here attains an actual 

 altitude of 0,000 feet, or 3,000 feet above the Snake — opportunity was 

 afforded for the prosecution of some interesting' detail examinations in the 

 sedimentaries which here niake up the northeast front of the range, the 

 results of which are given below. This locality lies about three miles to 

 the northwestward of Station XXV and four miles east-southeast of the 

 debouchure of Fall Creelc. As the little stream debouches from the 

 mountains its bed lies in a cauon across the high volcanic bench which 

 rests against the foot of the range, the relative position of which is shown 

 in an accompanying- section-diagram, the furtlier notice of which is de- 

 ferred to the section s])ecially devoted to the description of the physical 

 and geologic featiu-es of the lower valley of Snake Kiver. This volcanic 

 bench extends back from the river between one and two miles, when the 

 base of the range proper is reached, where, on the west side of the little 

 stream, that part of the section relating to the sedimentaries begins, ex- 

 tending: thence in a south-southwest course to the crest of the belbre- 

 mentioned fiont spur, and is as follows : 



Section north of Station XXV. 



1. Gray limestone, in places light granular subcrv'stalline, api)earing 

 in bench outcrop at foot of ascent, much broken up, and not satisfactorily 

 showing- the bedding-. J}\\) probably southwestward, though at one i^oiut 

 certain planes, probably joint structure, pitch to the X. 25° W. at an 

 angle of 80°. Contains Sicnopora or Fistiilqwra, crinoidal remains, Fen- 

 cstella, Spirifcr, Productns, a small Flati/ceras, &C., all characteri.stic forms 

 of the Carboniferous. This outcrox) is 800 to 1,000 feet above Snake 

 Eiver, the volcanics in places even reaching a higher level on the flank 

 of the mountain. 



2. Long- slope, with no rock exposures in situ, perhaps half a mile, 

 covered with groves of large pine, undergrowth, and open grassy plots. 



3. Pinlv, laminated brittle sandstone, almost a quartzite, forming' a 

 heavy ledge, dipping- gently southwestvvard, like the flagging of a dome 

 or arch. 



4. Bluish-drab, spar-seamed limestone, pertaining to a heavy ledge, 

 and contains a large BeUoroplwn. The bed di])S S. 45o W. at an angle 

 of 3U°, but at a neighboring exposure the inchnation changes to X. 50° 

 E., at an angle of 20°, indicating the axis of a fold or unduhition in the 

 sti-ata. A few fragments of black obsidian were observed in the soil at 

 this place. 



5. Gray, heavj'-bedded limestone, with irregnlar seams of rusty gTay 

 chert or siliceous bands, in low bench exposure 75 to 100 yards south of 

 X^o. 3. Dip 22° southwestward. Contains Froductus and a large Spirifcr 

 like S. earner atiis. 



0. Unexposed, sag. 



7. AYhite, iine, granular magnesian (?) limestone, a hea-vy ledge, 10 

 feet exposed ; dip 35°, southwest. 



8. Iicddish-buff indurated arenaceous bed. 



9. Dark-blue and gray siliceous limestone, with dark chert ; heavy- 

 bed, dip 35°, S. W. Spirifer^ Flcurotomaria. 



