6T.J0HN.] SECTION IN CARIBOU REGION. 399 



cal, or but little separated, tlie following deposits lying to tlie westward 

 and conformably superimijosed on the preceding. The section concludes 

 with the following and fartherest west-ljing deposits occurring in the 

 undulating uplands south of John Gray's Lake and occupying the inter- 

 val between the southwest base of the Caribou Eange and the northeast 

 foot of the narrow ridge which is designated as the " Gray's Lake ridge'' 

 in the preceding section devoted to the Willow Creek Basin. 



139. Laminated dark red sandstone, underlaid by red shales. This 

 ledge shows in an obscure outcrop in the shallow saddle on the crest of 

 the ridge immediately east of the extreme source of Tin-Cup Creek, 

 which at the point where we crossed attains an elevation of 1,700 to 

 1,800 feet above John Gray's Lake, or nearly as much lower than the 

 summit of Mount Caribou, a couple of miles to the northwestward. 



140. Space several hundred j'ards across, showing obscure exposures 

 of red shales. 



141. Brownish gray sandstone, obscure exposure. 



142. Unexposed space. 



143. Drab, spar-seamed, fragmentary limestone, dipping about 35^ 

 southwest ward. This forms a heavy ledge or deposit, plating the north- 

 east steep border-slopes on Tin-Cup Creek, and which is traced as far 

 as we could see in the direction of the strike, southeastward, where it 

 seems to be cut through at the abrupt easterly bend of the stream in 

 crossing this ridge. It is not very dissimilar to the limestone occurring 

 in the summit at Station XXVTII, but the absence here of the heavy 

 deposit of drab shales, which at the above locality underlies the lime- 

 stone, militates against the supposition of the identity of these lime- 

 stones. 



144. Eed shales, appearing in the valley of Tin-Cup Creek, a short dis- 

 tance above some abandoned, reservoirs for the placer mines lower down 

 this creek. 



145. Gray and brown conglomerate and sandstone. 

 14G. Eed shales. 



147. Gray, brown-weathered sandstone, heavy ledge. 



148. Eed and chocolate-colored shales. 



149. Gray, thin-bedded sandstone. 



150. Eed shales. 



151. Drab, fragmentary limestone, imperfect exposure of an ai^par- 

 ently heavy ledge. 



152. Chocolate-colored and red shales, with obscure exposures of 

 brown- weathered gray sandstone. 



153. Heavy-bedded, brown- weathered sandstone, in crest of rounded 

 divide. 



154. Space 200 to 300 yards, no exposure. 



155. Gray sandstone ledge. 



156. Unexposed space, 200 to 300 yards. 



157. HeaA^-bedded, gray sandstone and chocolate-colored shales, ob- 

 scure exposure. 



158. Eed shales, including chocolate-colored, thin-bedded sandstone, 

 imperfectly seen in the shallow valley of a tributary of Tin-Cup Creek. 



159. Heavy-bedded gray sandstone. 



160. Unexposed, space 100 yards. 



161. Gray, reddish weathered sandstone, in crest of low water-shed, 

 between Salt Eiver and Gray's Lake drainages. 



162. Unexposed. 



163. Buff gTay sandstone, and brown earth or shales, obscure exposure. 



