_EXPLORATIONS IN THE TRINIDAD CHANNEL._
In prosecuting the survey of the Trinidad Channel, we anchored, for
short periods each time, at a great many ports on its northern and
southern shores; and in crossing and re-crossing the channel we ran
lines of soundings which enabled us to ascertain roughly the general
conformation of its bed. Across the seaward entrance of the channel,
_i.e._, from Cape Gamboa on the north to Port Henry on the south, the
soundings gave a mean depth of thirty fathoms, showing the existence
of a sort of bar, while one mile inside of this the depth increased
to two and three hundred fathoms. This was just as we expected; the
bar across the entrance representing the terminal moraine of the huge
glacier which originally gouged out the channel, and whose denuding
action is abundantly recorded in the scorings, planings, and striations
so palpable on all the hard rocks of these inhospitable shores.
At Port Henry, on the southern side of the entrance to the channel, we
anchored several times. The scenery here is very grand. A clay-slate
rock enters largely into the formation of the hills, its highly
inclined strata forming jagged peaks and ridges of great height; while
the low-lying rock about the coast is a friable syenite traversed with
dikes of greenstone. Immediately to the south of our anchorage was a
lofty ridge of clay-slate hills, terminating above in a multitude of
vertical columns of rock, which from our position on board reminded us
of a cluster of organ pipes, and suggested the name which now appears
on the chart, of the "Organ-pipe Range." The aspect of the vegetation
is also different from that of other ports in these waters, owing
to the abundance of a veronica (_V. decussata_), which forms large
glossy-green bushes, covered with a profusion of snow-white flowers,
and so varies the otherwise monotonously green appearance of the beech
forest.
Only one party of natives was here seen. They at first approached us
very stealthily, paddling between the small islands off the eastern
entrance of the harbour, and after the usual interchange of signals
(waving of green boughs and caps), they came alongside. The boat was
similar in construction and size to those already examined at Tom Bay
and elsewhere; but we were now greatly struck at perceiving what a
load it could accommodate; for there were in it sixteen natives and
six dogs, besides provisions, weapons, and camp furniture. The party
consisted of three men, five women, and eight children; and although
they pulled only three oars (the women never taking part in this work),
yet they managed to get along at a fair pace. On their arrival they
were partially clad in seal skins; but in their eagerness to barter
with our seamen, for knives, tobacco, and such treasures, they soon
divested themselves of all artificial garb, and appeared in a state
of nature. It was noticed that the males, who conducted the barter,
compelled the women to give up their scanty covering. In the way
of provisions, the boat contained a supply of large trumpet shells
(_Concholepas_) in rush baskets, and the drinking water was carried
in little bark buckets. They encamped near us for the night, but
disappeared unaccountably the next day.
On our exploring the islets just mentioned, we found a large deserted
encampment, in which we counted the remains of nine native huts. The
refuse-heaps contained a good many seal and whale bones, besides
echinoderms, limpet and trumpet shells, the latter shell here taking
the place of the mussel. The trumpet shell (_Concholepas_) is found
about the entrance of the Trinidad Channel, inhabiting rocky places
immediately below low-water mark on the weather (_i.e._, the west) side
of islets which are exposed to the heavy wash of the outer ocean. I
have not seen the shell south of this latitude. The brown duck (_Anas
cristata_) was here tolerably abundant, and with the ashy-headed Brent
goose, and the two species of oyster-catcher, were in great request
with our sportsmen, being the only edible birds worth mentioning in the
western channels.
From Port Henry we shifted our base of operations to Wolsey Sound,
the next inlet to the eastward. Here we anchored in an apparently
well-sheltered cove, surrounded by lofty hills, but which we soon found
to our cost to be a sort of aerial maelstrom. A strong westerly gale
was blowing over the hill-tops, as we could see by the fast-flying
clouds; while below at the anchorage we experienced a succession of
fierce squalls (williwaws) from various quarters, with intervals of
complete calm; so that the ship kept swinging to and fro, and circling
round her anchors in a most erratic manner. Eventually one of the
cables parted; but with the other, aided by steam, we managed to
ride out the gale, and to thoroughly satisfy ourselves that Wolsey
Sound was not one of the anchorages to be recommended to passing
vessels. From the translation given in "Burney's Voyages," (vol. ii.,
p. 10), of the journal of Pedro Sarmiento de Gamboa, who discovered
the Trinidad Channel in the year 1580, it would appear that this is
the same anchorage which his sailors named "Cache Diablo" (devil's
box-on-the-ear), from the boisterous nature of the reception which they
experienced.
On the east side of Wolsey Sound the rock of the mountain masses is
for the most part a hard grey unfossiliferous limestone, irregularly
stratified, but sometimes showing a dip of 10° or 15° to the westward.
The most striking peculiarity of this rock consists in its solubility
under the influence of both fresh and salt water, and it is this
property that so often causes it to present a jagged honeycombed
appearance. I noticed that in many places fresh-water streams,
running over bare patches of this rock, had eaten away narrow gutter
channels, and that in other places where a broad sheet of water flowed
slowly--as from a turf bank--over a long gently-sloping table of
rock, an incrustation of hard calcareous matter had been deposited,
presenting a sort of "ripple-marked" appearance, and reminding one of
the effect produced when a film of slowly-moving water is submitted
to the influence of intense cold. When viewed from a distance, the
limestone hills presented a whitish bleached appearance, which
contrasted strangely with the sombre hues of the other greenstone
and syenite hills. Of this description was "Silvertop," a lofty and
conspicuous mountain on the south side of the Trinidad Channel, which
was frequently used by our surveyors as a landmark.
The next port to the eastward is Rosario Bay. It was named by Sarmiento
"Puerto de Nuestra Señora del Rosario." The rock formation here is
limestone, and of the kind above mentioned, but the effects of frequent
rain in washing away the more soluble parts of the rock were not only
manifested by the honeycombed appearance of exposed surfaces, but also
by the prevalence of caves of most irregular shape. Soon after we had
anchored, Sub-Lieutenant Beresford and I, who had gone away in the
skiff, were paddling around an islet with lofty and precipitous sides,
when we noticed in the face of a bare rocky cliff a suspicious-looking
dark opening, partly blocked up with stones, and situated about
thirty feet above the sea level. We ran the boat alongside the rocks,
and Beresford kept her from bumping while I climbed up the cliff to
reconnoitre. On clearing away a heap of stones and rubbish, I laid
bare a sort of niche in the rock, in which were portions of a human
skeleton, the long bones lying together in a compact bundle, as if they
had been so placed there when in the dried state. Not many yards from
this crevice we soon discovered a small cave in the rock, and partly
imbedded in the soil which formed its floor were a human jaw-bone and
fragments of smaller bones. On excavating the floor of the cave we
found it to consist of a stiff pasty greyish-white marl-clay, abounding
in small shells, amongst which were species of the genera _Patella_,
_Fissurella_, _Chiton_, and _Calyptræa_. On reaching a depth of about
one foot, we came upon a nearly complete human skull of immature age,
an otter skull with bones of the same, and the tooth of an _Echinus_.
The human bones obtained were part of the skeletons of two individuals,
one of whom must have been young, for the epiphyses of the long bones
were not quite cemented to the shafts. I noticed that the skull
presented a completely ossified frontal suture, although, from the
nature of the teeth and alveoli, the person to whom it belonged could
not have lived for more than twelve years or thereabouts. A tibia
found in the first depôt bore marks of having been chopped by some
sharp cutting instrument. From the fact of these bones being found
interbedded with marine deposits, coupled with what we know of these
islands having been elevated within recent times--I here refer to the
evidence afforded by raised beaches and old high-water marks in the
faces of cliffs--there is reason to believe that these bones were
deposited in the cave at a time when it was under water, that they
thus became surrounded by and imbedded in an ordinary marine shallow
water deposit, and that eventually, on the island being elevated
so as to raise the cave to its present position--thirty feet above
sea level--the surface deposit was reinforced by the percolation of
lime-charged water from the rock above, thus resulting in the formation
of the marl-clay surface-layer above mentioned.
We made different attempts at dredging, but as the bottom was
everywhere very rocky and the dredge in consequence continually getting
foul, we were not successful in obtaining many objects of interest.
However, among them there were specimens of a hydroid stony coral
representing two species of the genus _Labiopora_--one of which Mr.
Stuart Ridley of the British Museum has ascertained to be a species new
to science--and a fine orange-coloured _Astrophyton_ of a new species,
recently described by Mr. F. J. Bell as _A. lymani_.
On the north side of the Trinidad Channel we stopped for a time at
an anchorage near Cape Gamboa, which forms the north headland of the
entrance. At Cape Gamboa the rock is a clay-slate showing distinct
stratification, containing concretions of a whitish sandstone, and
dipping to the N.E. at an angle of about 45°. To the eastward of Cape
Gamboa is a limestone similar to that of the south shore. We did some
dredging here on a smooth sandy bottom, the principal results of which
were specimens of the _Chimæra_ (_Callorhynchus australis_), and
some curious Isopod Crustaceans of the genus _Serolis_. Another day
(March 28th) when sounding across the entrance of the Channel, we made
a heave of the trawl in thirty fathoms with most fruitful results,
obtaining a magnificent specimen of the orange-coloured _Astrophyton_
(_A. lymani_), several small rays and flat fish, large _Actinia_, a
new Crustacean of the genus _Arcturus_, starfishes, and a Cephalopod
Mollusc of the genus _Rossia_. On the evening of this day we were
fortunate enough to witness a most beautiful sunset effect. As the sun
disappeared from a western olive-tinted sky it seemed to be followed in
its descent by several horizontal bands of delicate rose-tinted stratus
clouds, which extended themselves in parallel lines over an arc of 45°,
and finally tapered away into the most delicate threads of silvery
light. In the east the dark purple-tinted clouds melted upwards into
the grey gloom of approaching night, and foreshadowed to us the advent
of another day of sunshine in this the only really fine and summer
month in these western channels.
At the head of Francisco Bay--which was the name subsequently given to
this anchorage--at the outlet of a small river, we one day made a very
large "take" of fish in a somewhat singular manner. A trammel net had
been placed across the mouth of the stream at high tide, and on the
tide falling had been examined and found to contain a fair number of
fish (mackerel). Some hours later two of our people were wading up the
river, and on coming to a depression in its bed, which was at about
the limit to which the tidal salt-water reached, they found an immense
collection of half-dead and living mackerel in a pool, in which--the
tide being then rather low--the water was almost entirely fresh. Here
they caught, with their hands, fish enough to fill a boat, amounting to
a gross weight of 4 cwt. The probable explanation of this lucky "take"
seems to be that the fish entered the mouth of the river with the flood
tide--as is their wont--and on attempting to retreat with the ebb found
their return to the sea barred by our net, and instead of endeavouring
to pass through the meshes preferred to move back into the brackish
water of the river. Here, as the tide fell still further and laid
bare banks of sand stretching across the stream, they became shut off
altogether from the sea, and at dead low tide the flow of fresh water
so predominated over the salt as to render them helplessly stupid, so
that they fell an easy prey to our sailors.
On the shores of this bay I came across a magnificent Winter's bark
tree, the largest which I have ever seen in the channels. Its smooth
and almost cylindrical stem was nine feet in circumference, and ran up
without branching to a height of thirty feet from the ground.
In cruising to and fro about the channel we frequently came across
whales. They were usually either "finners" or "sperms"; more commonly
the former. I saw only one "right" whale during the many months
which we spent in these waters. On the 17th of February we steamed
by a school of about twenty "finner" whales, and shortly after we
passed through a shoal of small red shrimps (_Galatheas_), which were
so densely clustered together as to give the water quite a scarlet
appearance. This accounted for the great gathering of Cetaceans.
Skeletons of whales in a very imperfect state were abundant about the
shores of this channel, and many were of large size. On the shore
of Francisco Bay I saw lower jaw bones which measured eleven feet
from condyle to symphysis. I looked, but in vain, for remains of the
Ziphioid Whales.
Some few miles to the eastward of Francisco Bay a deep inlet pierced
Wellington Island in a northerly direction. We were anxious to explore
it, as we thought it not unlikely that it might prove to be a navigable
passage, connecting Trinidad Channel with the Gulf of Peñas. At
length an opportunity occurred, and on a fine morning in the month of
March we steamed into this unsurveyed inlet. On fairly passing the
southern entrance, we found ourselves traversing a lane of water of
such glassy smoothness, and bordered by such straight running shores,
which were not more than half-a-mile apart, as to seem more like an
inland canal than (which it eventually proved to be) a strait leading
through a nest of breakers to an inhospitable ocean. Its eastern shore
exhibited the kind of scenery prevailing about the Guia Narrows; viz.,
round-topped hills with great bare patches of rain-worn rock extending
from the summits to a talus, which was covered with an uniform mantle
of evergreen forest, the latter encroaching upon the sea-beach. But
the country to the west presented a more pleasing variety, being
composed of low undulating slopes of grassy-looking land, with here
and there fissures or landslips exhibiting what seemed to us, as we
scrutinized them with our glasses, to be sections of a sedimentary
formation. We had hitherto seen nothing like this anywhere among the
western channels, and consequently I for one was extremely anxious to
land. However, the captain had to make the most of daylight for the
surveying work in hand, so that our conjectures as to the nature of
this formation remained unverified. When we had attained a distance of
twenty-five miles from the southern entrance of the Strait, the western
shore was found to be broken up into a chain of low islets, which in
time dwindled away into a great arc of submerged rocks, over which the
swell of the broad Pacific broke with great fury. This then was the
end of what is now known as the Picton Channel, and bold would be the
mariner who would attempt to traverse it, and thread his way through
such a maze of reefs and breakers. Among the islets at this, its
northern extremity, we found an anchorage, where we decided on stopping
for the night. As we cast anchor, a native boat approached, carrying no
less than twenty-three inmates, most of whom were males, and of a most
savage and treacherous appearance. They had with them several young fur
seals, recently killed, which they were glad to barter for tobacco or
biscuit. After stopping alongside for about half-an-hour, they paddled
away and were seen no more. On the following day we steamed back.
The rocky shores and islets of the Trinidad Channel bear abundant
indications of old ice action. These marks are not very apparent on
the coarse-grained friable syenite which is the common rock of the
district, but on the dikes of hard greenstone, with which the syenite
is frequently intersected, scorings and striations of typical character
may be seen. Close to the anchorage in Port Charrua, on the north side
of the channel, there is a broad band of greenstone on which I observed
very perfect examples of "crosshatchings," where the prevailing east
to west striæ were intersected by those of another system at an angle
of about 40°. These rock erosions, coupled with what we know from the
sounding-lead as to the contour of the sea-bottom, lead us to infer
that the Trinidad Channel was at some remote period the bed of a huge
glacier, which flowed westward from the Cordillera. That most, indeed,
of the other straits and channels of Western Patagonia were also at one
time occupied by glaciers is clearly testified by the markings on the
rocks.
There is a peculiar form of syenite rock not uncommon in exposed
situations on the hill-tops, which is composed of quartz, felspar,
and hornblende, the quartz occurring in crystals of about the size
of large peas. The felspar, being of a very friable nature, rapidly
succumbs to the disintegrating influence of the weather, and crumbles
away, taking with it the small particles of hornblende, so that the big
quartz crystals, when in the last stage prior to being dislodged, are
seen standing out in bold relief from the matrix. When this rock is
seen projecting in round bosses, through the turfy soil of a hilltop,
it looks at a short distance as if strewn with hailstones; and the
illusion is heightened on observing on its leeward side heaps of loose
quartz crystals, which have been completely weathered out from the
parent rock, and have been drifted by the wind into this comparatively
sheltered situation, as would be the case with hailstones under similar
circumstances.
But the most characteristic feature in the scenery of the western
shores of Patagonia is owing to the phenomenon of "soil motion," an
occurrence which is here in a great measure due to the exceptionally
wet nature of the climate. This slippage of the soilcap seems in this
region to be continually taking place wherever the basement rock
presents a moderately inclined surface. Some of the effects of this
"soil motion" are apt to be confounded with those due to glacial
action, for the soilcap takes with it in its downward progress not only
its clothing of trees, ferns, and mosses, but also a "moraine profonde"
of rock, stones, and stems of dead trees great and small, whereby the
hills are being denuded, and the valleys, lakes, and channels gradually
filled up. When we first entered the Western Channels my attention was
at once directed to this subject on noticing that the lower branches
of trees growing in immediate proximity to the seashore were in many
places withering from immersion in the salt water, and that in some
cases entire trees had perished prematurely, from their roots having
become entirely submerged. On looking more closely into the matter,
I noticed that sodden snags of dead trees, mingled with stones,
were often to be seen on the bottom of the inshore waters, and that
the beds of fresh-water lakes were plentifully strewn with similar
fragments of wood, the remains of bygone forests which had perished
prematurely. These circumstances are fully explained by the occurrence
of soil motion, for as the soilcap by its sliding motion, imparted
by gravitation, and aided by expansion and contraction of the spongy
mass, reaches the water's edge, the soluble portions are removed, while
its more durable contents are left to accumulate at the foot of the
incline. In this way rocks and stones may sometimes be seen balanced
in odd situations near the sea beach, simulating the "roches perchées"
which are dropped by a melting iceberg or a receding glacier. These
circumstances are all the more interesting from their occurring in a
region where the effects of old and recent glacial action are exhibited
to a marked degree. Planings, scorings, striations, and "roches
moutonnées" may, one or other, be almost invariably found wherever the
rock is sufficiently impervious to the disintegrating action of the
weather to retain these impressions. Thus they are nowhere to be seen
on the coarse-grained friable syenite, which is the common rock of
the district; but where this rock is intersected by dikes of the more
durable greenstone, the above-mentioned signs of former glacial action
may be seen well developed. I speak now of old glacial action, because
we have not found any glacier existing in the neighbourhood of the
Trinidad Channel, from whence they seem to have entirely receded; but
they are yet to be seen in the fiords of the mainland further north;
and in the main Straits of Magellan we had opportunities of studying
fine examples of complete and incomplete glaciers, exhibiting in all
its grandeur that wonderful denuding power which these ponderous masses
of ice exercise as they move silently over their rocky beds. There
are, therefore, in this region, ample opportunities of comparing and
differentiating phenomena, which have resulted from former glacial
action, and those which are due to soil motion--a force now in
operation.
Sir Wyville Thompson (_vide_ "Voyage of Challenger," vol. ii., p. 245)
attributes the origin of the celebrated "Stone Runs" of the Falkland
Islands to the transporting action of the soilcap, which among other
causes derives its motion from alternate expansion and contraction
of the spongy mass of peat, due to varying conditions of moisture
and comparative dryness; and this hypothesis is to a certain extent
supported by the occurrences which I now endeavour to describe. Here,
in Western Patagonia, an evergreen arboreal forest, rising through a
dense undergrowth of brushwood and mosses, clothes the hillsides to
a height of about 1,000 feet, and this mass of vegetation, with its
subjacent peaty, swampy soil, resting--as it frequently does--upon
a hillside already planed by old ice action, naturally tends, under
the influence of gravitation, combined with that of expansion and
contraction of the soil, to slide gradually downwards until it meets
the sea, lake, or valley, as the case may be. In the two former cases
the free edge of the mass is removed by the action of the water, in a
manner somewhat analogous to the wasting of the submerged snout of a
"complete glacier" in the summer time; whereas in the last instance a
chaotic accumulation of all the constituents of the transported mass
gradually takes place, thereby tending to an eventual obliteration of
the valley. It appears to me that the conditions which are said to have
resulted in the formation of the "Stone Runs" of the Falklands here
exist in equal if not greater force. There is a thick spongy vegetable
mass covering the hillsides, and acted on by varying conditions of
extreme moisture and comparative dryness; there are the loose blocks
of disintegrating syenite to be transported; and there are mountain
torrents, lakes, and sea-channels to remove the soil. That motion
of the soilcap does actually take place we have at least strong
presumptive evidence; but anything resembling a "stone run" remains
yet to be discovered. It would naturally suggest itself to the reader
that the above phenomenon attributed to soil motion might be accounted
for by a slow and gradual depression of the land, and I have carefully
sought for evidence favouring this view, but have found no reliable
sign whatever of subsidence; while on the other hand one sees raised
beaches and stones testifying to the ravages of stone-boring molluscs
at heights above the present high-water marks, which indicate that even
elevation of the land has taken place.
On May 6th, the winter season having then fairly set in, we bade adieu
for a while to our surveying ground, and commenced our northern voyage
to Valparaiso. Our course lay first through the sheltered channels
which separate Wellington Island from the mainland. As we rounded
Topar Island and entered Wide Channel, the heavy mist which had been
hanging around us all the morning, almost concealing the land from
sight, lifted at intervals like a veil, and exposed to view the noble
cliffs of bare greenstone rock which hemmed us in on either side,--here
and there streaked down their faces by long slender cascades of
water, extending from summit to base, and seeming to hang over us
like glistening threads of silver. On passing the southern outlet of
Icy Reach, we saw shining in the distance the sloping tongue-shaped
extremity of one of the Eyre Sound glaciers, whose bergs float out
through Icy Reach in the winter time and sometimes prove a serious
obstruction to navigation in these gloomy and mysterious channels. In
Chasm Reach, which we next traversed, the hills on either side rose
nearly perpendicularly to a height of 1,500 feet, their snow-capped
summits contrasting grandly with the sombre tints of their rocky sides;
so scantily clad with vegetation as to seem at a distance mere sloping
walls of rock.
In the narrowest part of this "reach," where the width was only
about half-a-mile, three native huts were seen established on low
projecting shelves of rock, and situated about a mile apart. To these
our attention was attracted by the long curling wreaths of grey smoke
ascending from their fires. As darkness was coming on, we did not
stop to examine them, but steamed on towards Port Grappler, where we
anchored for the night.
We got under way early in the morning of the following day, and
proceeded through the channel as far as Hoskyn Cove, an anchorage
just to the northward of the famous English Narrows. The morning had
been hazy and showery, but towards noon the mist cleared away, and
as we passed the English Narrows, a burst of sunshine completed the
dispersion of the hazy vapour and lighted up a scene of surpassing
splendour. The scenery here contrasted strangely with that of Chasm
Reach, for the steep hillsides now were richly clothed with a luxuriant
growth of primeval forest, and rising to a greater altitude, had their
summits capped with a broad mantle of snow, which showed to great
advantage against the deep blue of the sky. In the narrowest part of
the channel, where the flood tide was making southward in a rapid
stream, numbers of fur seals were gambolling in the water, and the
energetic movements of the cormorants testified to the abundance of the
fish.
Formerly the vessels of the Pacific Steam Navigation Company were
in the habit of running through these "Narrows," but of late years
the practice has been discontinued, on account of the difficulty of
managing the long vessels which are now in vogue. Therefore, excepting
an occasional man-of-war, the only vessels which at the present day
make use of the channels leading to the Gulf of Peñas are the steamers
of the German "Kosmos" line. The deciduous beech (_Fagus antarctica_)
here formed a great proportion of the forest growth, and as its leaves
were now withering, their autumn tints gave a variegated character to
the wooded scenery, a feature not observed farther south, where the
evergreen beech (_Fagus betuloides_) predominates. The _Campsidium
chilense_, a large trailing plant, was abundant and in full bloom, its
flowering branches usually depending in rather inaccessible places from
the upper parts of the trees to which it clung; and here we obtained
for the first time specimens of the loveliest of South American ferns,
the _Hymenophyllum cruentum_.
The morning of the 8th May broke wet and gloomy as we got under way and
initiated the next stage on our journey. All day long the rain fell in
torrents, and a fresh northerly breeze, blowing right in our teeth,
raised a heavy, chopping sea, which made the old ship heave uneasily,
and gave us a sort of foretaste of what we should have to encounter
next day on emerging from the Gulf of Peñas into the troubled waters
of the Pacific. Steaming thus against wind and sea, we made such slow
progress that night had fairly come on us when we crept under shelter
of the lofty hills which overshadow Island Harbour.
On the following morning we entered the open sea, and steered for
Valparaiso.