348 EEPOET UNITED STATES GEOLOGICAL SURVEY. 



dip 50'^ to 65°, K 15° to 40° E., charged with, a minute PseudomonotiSj 

 medium- sized Aviculopecfeii, Terebratula, Lincjulaj &c. Specimens of a 

 similar limestone, filled with the same fossils, the handsome little 

 Pseudomonotis occurring in great numbers, were brought me by Mr. Tom 

 Cooper, from Station XIII, a couj)le of miles west of Station XII. 



c. Buff and brick-red indurated arenaceous shales, with thin, shaly 

 limestone band, exjjosed 200 to 300 feet, but much thicker, and filling 

 the Canada between the ridges of Stations XII and XIII, which are here 

 about a third of a mile apart. 



d. Dark brown-gray, fragmentary, slightly arenaceous limestone, a 

 rather heavy ledge occurring in the crest of Station XII ridge ; dip 50°, 

 N. 15° to 70° E. This rock contains numerous fossils, Lingula, Tere- 

 hratula, Avmdopecten, a large and small Pseudomonotis, Myacites f, &c. 



e. Grassy, undulating upland, with light-red or pink trachytic debris 

 scattered over the surface, but no rock exposures in situ observed over a 

 space of about one-third mile in width, north of Station XIII ridge. 



/. Gray, bufi'-mottled, fine-grained, spar-seamed hmestone, with cherty 

 bands, apparently a thick bed ; dips 75° X., 30° E. 



g. Heavy ledge, reddish-buff, very hard, fine-grained sandstone, stand- 

 ing vertical, or slightly inclined from vertical north, exposure 50 yards 

 north of last above bed. The outcrop shows angular fragments, and 

 intersected by joint structure. 



h. Dirty gray, thin-bedded, spar-seamed limestone, debris exposure, 

 not showing ledge in situ. It is succeeded a few yards north by a 

 ledge of very hard dark-gray limestone, containing an obscure fossil 

 resembling Aviculopecten. but too indistinct for identification; dips 45° 

 to 50°, S. 35° W. 



*. Eeddish sandstone and arenaceous shales. A much broken-up 

 exi^osure in crown of ridge, perhaps one mile north of Station XIII 

 ridge, and apparently filling the narrow depression or cauada just to 

 the north, out of which it is eroded. 



¥. Thin-bedded dark-gray limestone, with minutely comminuted fos- 

 sils ; dips 55° to 65°, X. 35° to 40° E. Exposed in south slope of ridge, 

 perhaps a quarter of a mile north of crest of sandstone ridge. Above 

 occurs the following ledges : 



W. Heavy beds of gray limestone, associated with brown, laminated 

 earthy, indurated layers, slightly inclined from the vertical northward, 

 although the exposure is but a few yards removed from the preceding 

 bed. This ledge contains an obscure Lamillibranch and fragments of 

 Ceratitesf and it forms a marked feature in the south-facing slopes, where 

 it may be traced for a distance to the southeastward and northwestward. 



¥. Thin-bedded gray limestone, exposed but a few yards north of last 

 above-mentioned ledge ; dip almost vertical, or at a steep angle to the 

 south. 



I. In the saddle of the narrow caiiada a short distance north of the 

 last ridge, red shaly deposits are seen in washes. 



m. Elesh-gray limestone, with pink chert layers, 8 feet ; overlaid by 

 a heavy deposit of gray, fragmentary, brecciated, siliceous limestone, 

 100 feet or more; dips 60°, S. 35° to 40° W. Contains fossils, but too im- 

 perfect for identification. This ledge forms a heavy platiag to the south- 

 faciQg slope of the culminating plateau, two and a half miles north of 

 Station XIII ridge. 



n. A vertical space of 200 feet or more without exposures follows, and 

 then a heavy deposit of siliceous matter is met with, rising up into the 

 high ridge. It is composed of reddish, pink-mottled, buft', gritty beds, 

 the decomposition of which produces a reddish-brown soil, underlaid by 



