Page:Journal of the Royal Geographical Society of London, Volume 1 (2nd edition).djvu/198

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166 Geography of Tierra del Fuego, three thousand five hundred or four thousand feet above the sea; for the mountains, whose height does not ,exceed three thou?d, are, during the summer. frequently free from any, excepting in holes, where a large quantity is accumulated by drifting, and pro- tected from the sun. The strait hem is quite free from islands, and it is a remarkable fact, that. where the groens?oae formation terminates, there the islands cease to appear. The slat? formation continues as far as Freshwater Bay, where the stratified rocks leave the coast and extend backwards in a north-west direction. The soil then becomes apparently a mixture of decomposed slate and clay; the slate gradually dizappearing on approaching to Cape Negro, where the rock partakes of the cha- racter of the east coast. Here again we observe, along with the change of geological character, the reappearance of islands, the soil of which is clayey, but with masses of granite, hornblende rock and clay slate protruding in many places through the superfi- cial soil, which, although it yields a poor grass, is entirely destitute of trees. In that portion of the Strait to the eastward of Cape Negro the hills are remarkable for the regularity and parallelism of their direc- tion, and their general resemblance to each other. On the north shore, near Cape Gregory, a range of hills commence? suddenly, with rather a precipitous ascent, and extends for forty miles to the north-east, where it terminates in detached rocky hills. The south- western end of the range is a ridge of flat-topped land covered with soil, but with here and there a protruding maas of primitive rock; one of these appeared to be of s?enite or granite. The north-eastern end of this range is perhaps more bare of soil, and, therefore, exposes the rock, which shows itself in detached hills. Precisely similar in appearance and direction is a range on the south shore, about fifty miles in length, commencing at Cape Monmouth and terminating in detached hills in the vicinity of the south side of the First Narrow. The courses, also, of both the First and Se- cond Narrows, which are just within the eastern entrance of the strait, are nearly parallel w?th these hills; and the smaller ranges of eminences, Elizabeth Island and the clitfy land of Cape Negro, where the clay formation commences, all tread to the N.N.E., preserving a general resemblance of form and character to the two ranges above-mentioned. The irregularity of the topographic features of the more weztern .portion of the Strait, combined with its confused assemblage and ?mmense number of islands and rocks--the regularity of the strata, Jthe coinciding parallelism of all the bays, channels, and sounds, --and the total absence of islands in the central pertion or slate formation, together with the remarkable similarity of the direction of the hills and coast line, and the stratification-of the north- Dig,tiz?d by Google