352 EEPOKT UNITED STATES GEOLOGICAL SURVEY. 



posits is met Tritli, sliowing a tliiolmess of several liimdred feet, with a 

 general incliuatioii of 20° to 35^, about S. 35° W. At one point in Sta- 

 tion XVI ridge the ledges sliow, in tlieii- northerly dip, a short undula- 

 tion, beyond which, north, they resume their southwesterly inclination 

 as far as traced. The exposures here referred to aflbrd the follomng 

 detail section : 



Section in oiorthern portion of Willoiv Creelc ridge, througJi Station XVI. 



1. In the southeast flanlc of Station XY, 300 to 400 feet below the sum- 

 mit, soft, gray, laminated shaly sandstone, with oliscure vegetable im- 

 pressions, interl>edded with reddish and light gj^psiferous shales, out- 

 croi>s, showing a thickness of above 100 feet; dip 28°, S. 40° W. 

 These deposits are capped by the basalt in Station XV, there being no 

 evidence of other volcanic deposits interposed between the basalt and 

 the sedimentaries. The contact of the latter deposits was hidden by the 

 debris accumulations at the foot of the basaltic walls, so that it was not 

 ascertained to what extent or in what manner the contact of the igneous 

 matter affected the sedimentary deposits over which it flowed. From 

 the above exposure the line of the section was carried nearly at right 

 angles to the strike of the sedimentary beds, or in a north-northeast 

 direction. 



2. The next exiDosure, 300 yards distant, appears as a low comb formed 

 by a heavy bed of similar gray, thin-bedded sandstone, dipping at a 

 little steeper angle. It is cross-bedded, the planes of false bedding fac- 

 ing the northeast. 



3. At foot of steeper slope, 100 yards beyond the last, similar but still 

 heavier deposits of softish gray sandstone are exx^osed as a plating in 

 the acclivity, dipping at an angle of 35°. 



4. In the crest of the ascent, which is determined by the strike of the 

 beds, a few hundred yards from the foot of the last ledge, the sandstone 

 changes to a coiu-se aggregation of water- worn but not rounded siliceous 

 pebbles, forming a Mable, thin-bedded, conglomeritic rock of a rusty 

 buff and reddish tinge, the disintegration of which has strewn the sur- 

 face with fine gravel. The estimated thickness of this ledge is about 50 

 feet ; dip 25°, S. 40° W. The coarse materials show a variety of color. 



5. The above deposit is immediately succeeded below by a heavy bed 

 of deep-red, fine arenaceous shales, probably at least 50 feet thick, which 

 outcrops in the southern slope of a shallow saddle, in the bed of which 

 appears — 



6. a, Gray sandstone, passing below into a heavy deposit made up 

 of, &, gray and reddish tinged sandstone, vdth, c, interlaminations of 

 indurated ferruginous material, reach a thickness of several hundred 

 feet. In the summit of Station XVI plateau, the above layers are under- 

 laid by an equal or considerably gTeater thickness of sunilar arenaceous 

 deposits which occur in the following order : f7, ledge of hard, buff, rusty 

 weathered sandstone ; e, softish buff sandstone ; /, ledge of hard, rusty 

 gray and brownish sandstone; obliquely and horizontally laminated, and 

 containing obscure vegetable remains like fragments of the trunk or 

 limbs of trees. The latter ledge shows a local disturbance, in places 

 being raised up into low bulging or sharp crested narrow ridges, and 

 dipping at angles of 20° to 35°, E. 25° S. to X. 5° W., but elsewhere 

 showing general conformity with the overlying deposits. These depos- 

 its extend up into the culminating point at Station XVI, to the north of 

 which the hill falls away over steep slopes into a deep saddle connecting 

 it with the higher crest a mile and a half distant, in which the highland 



