locality in this latitude should have been thus accidentally struck, and it is but
reasonable to conclude that the spot laid down in the old charts as a “ Sunken
land ’ should still be the shallowest, there is good ground for supposing that
the depth continues gradually to decrease from the westward locality, where it is
7 48 fathoms, to the reputed position of the Sunken land. The probability is
enhanced, moreover, from the circumstance of its being only twelve miles to the
eastward of the meridian laid down in the French map by M. Fleuiieu as that of
“ Buss.” Lastly, we find that if a line passing through the axis of volcanic
action in Iceland (that is to say, extending from its north-easterly to its southwesterly
extremity) were produced in the latter of these two directions, it would
as nearly as possible cross the position of the Star-fish sounding and the “ Sunk
land ” so often refeiTed to. Now we know that subterranean forces have been
in active operation in the direction of Iceland at a very recent period, and that
a submergence has taken place of certain volcanic islands which were suddenly
heaved up from the sea-bed. Apart from other evidence, this fact is obviously
of less value than it would have been had the submergence of the islands taken
place gradually; but, viewed in conjunction with the subsidence known to have
been taking place for several centuries along the southern shores of Greenland,
and in the absence of sufficient reason for repudiating the testimony of the early
Scandinavian, Venetian, and French hydrographers, it leaves very little room for
doubt that a vast area of the sea-bed, involving the whole of these positions,
has shared in the submergence.
In all soundings demanding accuracy, it has been customary to determine the
depth by one operation, and to secm-e the specimen of bottom by another. On
the present occasion, the depth (1260 fathoms) having been ascertained, a new
form of “ deep-sea dredge ”* was lowered; but, in consequence of its partial failure,
a second apparatus (namely, the conical cup) was employed, 50 fathoms of
line in excess of the recorded depth being paid out in order to ensure the
unchecked descent and impact of the instrument at the bottom. The “ dredge ”
* The “ deep-sea dredge ” is really, what the name implies, a dredging- and not a sounding-machine.
I t was devised by the Chief Engineer of the ‘ Bulldog,’ Mr. Roughton. Although somewhat imperfect,
owing to the necessity for carrying out the design with such materials as wore available at sea,
it might readily be made a most efficient instrument. For natural-history purposes it is obvious that
a dredging instrument would always he preferable to one which merely closes on such portion of the
surface as it happens to come in contact with.
J i
had already brought up a small quantity of unusually pure Globigerina-deposit
and some small stones. The second instrument came up quite full of the deposit :
but it was neither so free from amorphous matter, nor did it contain any of the
small stones. Adhering, however, to the last 50 fathoms of line, which had
rested on the ground for several moments, were thirteen Ophiocomæ, varying in
diameter across the arms from two to five inches. None of these relaxed their
grasp on emerging from their natural element, hut continued, for a considerable
period after detachment from the sounding-line, to move about their spine-
covered arms, thus clearly proving that, although their continued adherence may
have depended in some degree on clonic spasm caused by the diminution of
pressure, or on the entanglement of their spines in the fibres of the hempen line,
their vitality was at all events far from extinct.
Here then we have the accuracy of the first operation conclusively established
by the two succeeding ones ; the nature of the bottom brought up by the dredge
verified by that procured in the conical cup ; the proof that fifty fathoms and no
more rested on the ground supplied in the correspondence of the three soundings ;
and, so far as the sounding apparatus is concerned, proof that the Star-fishes had
no opportunity of attaching themselves to any portion of the line except that
which rested on the bottom. I f we examine the remaining evidences, we shall
find that it is impossible to arrive at any other conclusion than that the Starfishes
were captured on the sea-bed itself, and not at any point intermediate
between it and the surface.
Commencing with the habits of the hard-shelled Echinoderms, there is ample
evidence of their being essentially ground-living animals—that is to say, unfitted
both in virtue of their structure and specific gravity to raise themselves
to any distance, or for any lengthened period, from the bottom. Edward
Forbes states that “ they are almost all free animals, creeping about at the
bottom of the se a ;” and adds that their coriaceous skin, which is commonly
strengthened by calcareous plates or spines, “ distinguishes them from the
Medusæ, free-swimming animals of the most delicate and membranous texture”*.
In Professor Owen’s recent work on Palæontology, the characters of the
Echinoderms are given as foUows ;■—“ Marine, commonly free repent animals,
with the integument in most perforated by erectile tubular tentacles, hardened
* ‘British Star-fishes,’ by Edward Forbes. London, 1841 : Introduction, p. 12.