No. I.] GEOGNOSTICAL OBSERVATIONS. 527 



passes betwixt high but even ranges of round-backed hills, between which and 

 the water there are interposed high and steeply-rounded banks of a clayey 

 soil, well covered with trees. 



The beds of the Mountain Torrents, which open into the river here, contain 

 many fragments of a dark red sandstone, which would seem to indicate that the 

 old red sandstone formation occurs in these mountains. The river contracting 

 to the width of a hundred and twenty yards, at length forces itself through the 

 Rocky Defile, a narrow channel which it has cut during a lapse of ages in the 

 shelving foot of a hill. The channel is bounded by perpendicular rocky walls, 

 varying in height from fifty to a hundred and fifty feet, above which there is 

 imposed an immense body of fine sand. The form of the land would lead one 

 to suppose, that the river at some distant period, pent in by the rock, formed 

 a long narrow lake, whose superfluous waters were discharged by a magnificent 

 cascade — an opinion which is countenanced by the figures of the sandy ridges, 

 which rise immediately above the rapid to the height of five hundred or six 

 hundred feet. The walls of the rapid consist of a very dark purplish-red com- 

 pact felspar rock. It probably belongs to the old red sandstone formation, and 

 seems to rest upon or to alternate with a rock, which seems to be a variety of the 

 old red sandstone, and which is composed of light-reddish and greyish felspar 

 and quartz, the former indistinctly crystallized. This latter rock is everywhere ex- 

 posed in the bed of the river for ten or twelve miles below the rapid. For this space 

 the river flows about three hundred feet below the level of a sandy plain, which 

 is bounded to the westward at a considerable distance, by a continuation of the 

 range of hills through which the river forces itself at the Bear-Lake Portage, 

 and to the eastward and northward by a lofty ridge of trap rocks, which consti- 

 tute the famous Copper Mountains. The surface of these plains is variegated 

 by some small conical sandy eminences, and ornamented by clumps of mode- 

 rately large spruce trees (thirty feet high), amongst which the River Mouse 

 winds, and falls into the Copper-Mine River from the westward. In the beds 

 of the torrents that intersect the plains, there are found fragments of reddish- 

 grey granular foliated limestone* of deep red sandstone, of grey sandstone com- 

 posed of grey quartz and felspar, probably a variety of the preceding, and of 

 red sienite, all members, perhaps, of the old red sandstone formation, or that 

 which lies under coal, and occasionally alternates with transition rocks. There 

 occur also fragments of pale red sandstone, composed principally of quartz, and 



