8T.Jon.N-.] REGION OF STATIONS XXV AND XXVI. 387 



tion in the imperfectly exi^osed belt to the north. But still farther in 

 that direction, in the lower slopes, -vrirtish belts of alternatmg- heavy 

 limestone and red shales and sandstone deposits occur, the equivalents 

 of which are less satisfactorily demonstrable, altliongh they recall the 

 alternations of calcareous and siliceous deposits elsewhere so character- 

 istic of the Upper Carboniferous. These dei^osits are probably farther 

 complicated by their proximity to a much disturbed belt which lies 

 close along the northeast border of the range in this \icinity. Sta- 

 tion XXVI ridge holds the same relative position between Pyramid and 

 McCoy Creeks as that of XXV below the caiion of the former stream ; 

 that is, the abrupt front barrier along tha Snake Valley. From the 

 back of the northeast spur, along which the above section passes, at 

 the point capped by the red sandstone No, 12, looking to the westward, 

 in the rugged, much-cut-uj) northwest slopes of Pyramid Creek Caiion, 

 a short distance above or just within the debouchiu-e, the strata exhibit 

 an interesting fold, a rough sketch of which is introduced in- an accom- 

 panying plate. The nucleus of the fold shows light-gray deposits, prob- 

 ably Umestone, undulating or crumpled along the crest of the arch, and 

 pitching sharply on either flank, where, however, they are less distinctly 

 traced. To the northeast of the latter locaUty a much-disturbed narrow 

 belt, in which the strata are apparently tilted almost vertical, or with 

 steep southerly dip, is followed by northeasterly-dijiping red deposits, 

 which, however, in the steep slopes in the west side of the debouchure 

 and lower down in the vicinity of the Pyramid, are observed to incline 

 in the opposite direction, southwestwardly. Above this fold, southwest, 

 succeed heavy deposits of red shales and sandstones, including light- 

 drab calcareous deposits, which continue up the canon and rise into the 

 rugged monoclinal crest of Station XXV ridge, dipping southwestward. 

 The same series also occurs on the southeast side of the caiion, reaching 

 well up into Jurassic horizons, the strike trending from a southeast 

 round more to an east course in this latter quarter. The stratigraphic 

 display, as seen from the high point a mile north of Station XXVI, is of 

 exceeding interest. At a glance it shows the great monoclinal ridge of 

 Station XXV, the superstructure of which is built entirely of the rich- 

 toned materials of the Jura-Trias, and ax)parently based upon a much 

 disturbed foundation of Upper Palaeozoic rocks. Xorth of the latter 

 station mention was made of the jjrobable existence of a fold in the 

 Carboniferous beds in the foot of the mountain bordering the valley. 

 It is barely possible that the latter fold has some intimate, even direct, 

 connection with the similar disturbed belt within the debouchure of 

 Pyramid Creek above noticed. Yet this is not quite certain. In the 

 former quarter erosion and subsequent volcanic eruptions have destroyed 

 and concealed the outlying northeast flank of the fold, so that the means 

 are wanting for a more critical comparison of the phenomena ui that 

 quarter with the apparent greatly-disturbed corresponding belt in the 

 mouth of Pyramid Creek Canon. The lower limestone deposits of the 

 above section, including also the limestone and quartzite in the low ridge 

 to the northeast of the saddle over which the trail passes, may with a 

 degree of warrant be provisionally referred to the Carboniferous. But 

 the latter exposures occur quite beyond or outside the above-mentioned 

 uplift, and probably belong to the southwest flank of a fold the axis of 

 which may lie in the mountains on the opposite side, or within the area 

 of the Snake Valley. The strata are pitched headlong into the inter- 

 vening synclmal, and much pinched, as indicated by their highly-tilted 

 position in opposite directions in the section more or less well-displayed 

 in the entrance to Pyramid Creek Cauon. 



