sr. john.] GROS VENTEE RANGE. 449 



where it replaces the Quebec in the mountain-flank. To the south, how- 

 ever, a hig'h Archaean spur, carrying on its ridge a plating of quartzite, 

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

 land slope and abruptly terminated 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 development of red deposits, sandstones and 

 arenaceous shales, beneath which Professor Bradley noted the occurrence 

 of limestones, probably of Carboniferous age, which, still farther south, 

 merge into the Carboniferous deposits at the head of the Grand Canon 

 of the Snake. 



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

 the siunmit of the isolated peak on which Station XLIV was established, 

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

 accompanying plate. 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 b) bluish-drab, partially indu- 

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

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

 pale pink and cream-colored sandstones appear (2) dipping 30° to 40° 

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

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

 separating 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 buff magnesian limestone occurs, in 

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

 Bewiprow^es-likebrachiopods. This, doubtless, is a remnant occupying 

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

 pearance, it may either belong to the Magara or Carboniferous. Above 

 the latter exposure the surface shows immense quantities of quartzite 

 debris, and, as we ascend, gneissic fragments become more and more prev- 

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

 foot of the peak of Station XLIY. The angular quartzite and but little 

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

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



The northwest face of the mountain shows an amphitheatre,in the bed 

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

 watering cosy mountain meadows dotted with the many lined blossoms 

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

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

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

 bedding is much contorted and obscure, though it appears to dip mod- 

 erately northeastward. 



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

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

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

 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 locahty ; and 

 wherever a little platform allows the retention of the soil thus derived,. 

 29 GS 



