ST. JOHN.] GROS VENTRE RANGE. 449 



wliere it replaces the Quebec in the mountain-flanlc. To the south, how- 

 ever, a liigh Archseau spur, carrying- on its ridge a plating of (luartzite, 

 and probably, also, Quebec limestones, breaks the continuity of the fore- 

 laud slope and abruptly terndnates in steep declivities facing the east- 

 ern escarpment of the Lower Gros Ventre Buttes. To the south of this 

 spur a few miles, as we shall see presently, the mountains are largely 

 made up of an enormous develoi)ment of red dei^osits, sandstones and 

 arenaceous ;;hales, beneath which Professor Bradley noted the occurrence 

 of limestones, i^robably of Carboniferous age, which, still farther south, 

 meige into the Carboniferous deposits at the head of the Grand Caiion 

 of the Snake. 



Passing up over the foreland north of the above-mentioned spur to 

 the summit of the isolated peak on which Station XLIV Avas established, 

 the northwest flank of the mountain exhibits the section shown in. the 

 accompanying i)late. At the foot of the ascent, the Quebec limestones 

 show in ledges lapping up on the slope. They consist of (3 c) drab, even 

 and thin-bedded, rough-weathered, fragmentary layers, underlaid by 

 (3 a) a similar heavy ledge, separated by (3 h) bluish-drab, partially indu- 

 rated shales, all dipping 25° to 35°, W. 50° IsT. In the deeper ravines 

 ledges of rusty -red quartzite and hard, laminated, reddish -bulf and 

 pale pink and cream-colored sandstones appear (2) dii^ping 30° to 40° 

 northwestward, and which, higher in the slope, form the crest of the 

 ridge along the north side of the canon which rises in Station XLIV, 

 separatnig this from the before-mentioned high Archaean spur. The 

 latter deposits hold the position of the Potsdam quartzites. Still higher 

 in the slope a slight fold in the strata was observed, and just beyond 

 this a limited outcrop of (4) light buif magnesian limestone occurs, in 

 which a few very imperfect fossils were found, crinoidal remains and 

 ^c>H/;;ro»iYes-likebrachiopods. This, doubtless, is a remnant occupying 

 a slight sag in the undulating strata, and, judging from its lithological ap- 

 pearance, it maj" either belong to the Niagara or Carboniferous. Above^ 

 the latter exposure the surface shows immense quantities of quartzite 

 debris, and, as we ascend, gneissic fragments become more and more i>rev- 

 alent, until, finally, their native ledges are reached in the immeiliate 

 foot of the peak of Station XLIV. The angiilar quartzite and but little 

 abraded gneissic debris is piled in huge ridges, like moraius, which, for 

 the most part, are covered with a dense forest of pines. 



The northwest face of the mountain shows an ami)hitheatre,in the bed 

 of which deep baidcs of snow lay, from which trickled pretty rivulets,, 

 watering cosy mountain meadows dotte^^l with the many hued blossoms, 

 of tiny, moss-like plants. A sharp Archcean spur defines the eastern 

 wall of the amphitheatre, its crest weathered into pinnacles, and but- 

 tressed by the peculiar Aveathered forms common to these rocks. Their 

 bedding is much contorted and obscure, though it apj)ears to dip mod- 

 erately northeastward. 



Ascending the abrupt-falling western spur leading to the summit, 700 

 to 800 feet higlier, heavy blocks of a light-gray quartzose gneiss are en- 

 countered, showing breakage or cleavage structure in two marked jdanes, 

 the one inclining north at an angle of 40°, and the other S. 45° W., at 

 angles of 70° to 80°, the laminated structure being extremely obscure, 

 and only as seen in mass does it exhibit what appears to be the true 

 bedding, inclined as before stated, northeastward. The process of deg- 

 radation by which these hard Archaean rocks are reduced to the condi- 

 tion of finely pulverized soils is well displayed at this locaMty ; and 

 wherever a little platform allows the retention, ot the soil thus derived^ 

 29 GS 



