Observations on Terra del Fuego. 405 



alpine plants, which all spring from the mass of peat, and help to com- 

 pose it. The central part of Terra del Fuego, where the clay-slate for- 

 mation occurs, is most favourable to the growth of trees ; on the outer 

 coast, the poorer granitic soil, and a situation more exposed to the vio- 

 lent winds, do not allow of their attaining any great size. Near Port 

 Famine I have seen more large trees than any where else : I measured 

 a "Winter's-bark, which was four feet six inches in girth, and several of 

 the beech were thirteen feet. Captain King also mentions one of the 

 latter, which was seven feet in diameter seventeen feet above the roots. 



f Zoology. — The zoology of Terra del Fuego, as might have been ex- 

 pected from the nature of its climate and vegetation, is very poor. Of 

 mammalia, besides Cetace.a and Phocee, there is one bat, a mouse with 

 grooved front-teeth (ReUhrodon of Waterhouse), a fox, sea-otter, guanaco, 

 and one deer. The latter animal is rare, and is not, I believe, to be found 

 south of the Straits of Magellan, as happens with the others. Observing 

 the general correspondence of the cliffs of soft sandstone, mud, and 

 shingle, on the opposite sides of the Strait, together with those on some 

 intervening islands, one is strongly tempted to believe that the land was 

 once joined, and thus allowed animals so delicate_and helpless as the tu- 

 cutuco and reithrodon to pass over. The correspondence of the cliffs is 

 far from proving any junction ; because such cliffs generally are formed 

 by the intersection of sloping deposits, which, before the elevation of the 

 land, had been accumulated near the then existing shores. It is, how- 

 ever, a remarkable coincidence, that, in the two large islands cut off 

 by the Beagle Channel from the rest of Terra del Fuego, one has cliffs 

 composed of matter that may be called stratified alluvium, which front 

 similar ones on the opposite side of the Channel, while the other is ex- 

 clusively bordered by the older rocks : in the former, called Navarin 

 Island, both foxes and guanacoes occur ; but in the latter, Hoste Island, 

 although similar in every respect, and only separated by a channel a little 

 more than half a mile wide, I have the word of Jemmy Button for saj'ing 

 that neither of these animals are found. I must confess to an exception 

 to the rule, in the presence of a small mouse, of a species occurring like- 

 wise in Patagonia. 



The gloomy woods are inhabited by few birds ; occasionally the plain- 

 tive note of a white-tufted tyrant-flycatcher may be heard, concealed 

 near the summit of the most lofty trees ; and more rarely the loud strange 

 cry of a black woodpecker, with a fine scarlet crest on its head. A little 

 dusky-coloured wren (Scytulopus fuscus) hops, in a skulking manner, 



vations showing that, in England, the leaves fall earlier in a warm and fmo 

 autumn, than in a late and cold one. This change in the colour heing re- 

 tarded in the more elevated, and, therefore, colder situations, must bo owing 

 to the same general law of vegetation. The trees of Terra del Fuego 

 during no part of the year entirely shed their leaves. 



