Feb. 1827. ADMIRALTY SOUND. 59 
being shoal,—from the very slight tide-stream,—and from the 
information of the Natives; who evidently intended to tell us 
we could not get out to sea,—that we did not consider it worth 
while to make another examination. 
I have before observed that the strata of the slate rocks, in 
the Strait, dip to the S.E.; and I found that they dip similarly 
all the way to the bottom of this inlet, which I named Admiralty 
Sound. 
The north side, like that of the Gabriel Channel, is steep, 
without indentations, excepting where there is a break in the 
hills; but on the south shore there are many coves, and bights, 
the cause of which is shown in the accompanying imaginary 
section of the Gabriel Channel. ‘The same cause operates on 
the outline of the north shore of the reach of Cape Froward, 
westward as far as Cape Holland, where the rock assumes a 
still more primitive form. Its general character, however, is 
micaceous slate, with bread veins of quartz; the latter being 
particularly conspicuous at Port Gallant. 
The following slight sketch, intended to represent an ima- 
ginary section of such an opening as the Gabriel Channel, 
may also serve to give a general idea of many Fuegian ancho- 
rages ;—of deep water passages existing between the almost 
innumerable islands of Tierra del Fuego ;—and of the effects 
of those sudden, and violent gusts of wind,—so frequent and 
dangerous,—commonly called hurricane-squalls,* or williwaws. 
* No canvas could withstand some of these squalls, which carry spray, 
leaves, and dirt before them, ina dense cloud, reaching from the water to 
the height of a ship’s lower yards, or even lower mast-heads. Happily their 
duration is so short, that the cable of a vessel, at anchor, is scarcely 
strained to the utmost, before the furious blast is over. Persons who have 
been some time in Tierra del Fuego, but fortunate enough not to have 
experienced the extreme violence of such squalls, may incline to think 
their force exaggerated in this description : but, it ought to be considered, 
that their utmost fury is only felt during unusually heavy gales, and in 
particular situations; so that a ship might pass through the Strait of 
Magalhaens many times, without encountering one such blast as has 
occasionally been witnessed there.—R.F. 
