half an inch in length, and evidently just broken oif from the stone to which it
must have been attached, inasmuch as the lleshy matter was perfectly fresh at
the point of fracture—and lastly, a minute SpirorUs and two shells of Tmncatu-
lina lohata still adherent to small stones and appai'ently alive. Leading the
discussion of the conditions essential to the maintenance of animal life at great
depths to be set forth in another chapter, two very remarkable facts remain to
be noticed in connexion with this sounding. The first of these is the almost
enth-e absence of any soft deposit at a spot -which, according to the evidence
aiforded by the progressive depths noted on either side, would appear to be the
deepest portion of the sea between the Faroe Islands and the south-west part of
Iceland. The second is the rolled condition of the basaltic gravel.
Now, although it is quite clear that the small trace of mud brought up in this
sounding is, of itself, no proof that soft deposit does not occur in considerable
quantity, the absence of such deposit is rendered probable by the presence of
permanently sessile Annelids and Foraminifera; inasmuch as these creatures
could not exist at all, save at the immediate surface of the sea-bed, or in water
free from currents of sufficient velocity to dislodge or remove them.
On the other hand, the rounded basaltic gravel would, at first sight, appear to
countenance the existence of a rolling action such as a current would produce.
And doubtless these pieces of gravel have, at one time or other, been reduced to
then* present form by such a force. But certain appearances on their surface
would indicate their long-continued retention at the point û'om which they were
brought up. Thus, although for a depth of about -^uth of an inch the basalt
is of the most compact kind, the stone has completely changed colour from its
normal glistening black to an ochreous yellow, owing to long immersion. This
ochreons layer is in other respects identical with the mass within, and cannot
possibly be mistaken for an incrustation formed from without. In a sounding
obtained early this morning, rounded masses of basalt were again met with, but
the depth in this case was only 64 fathoms. I f the former were dropped from
drifting icebergs, in their rolled condition, it must have been under a -widely
different order of things from that in operation now ; for no iceberg has ever
been kno-wn to traverse this region. I t is probable, therefore, that the bed of
the ocean has subsided, and that these rolled masses have rested in their present
position from a period when currents or tides of sufficient power to produce their
rounded shape swept across it. But although no current now exists in this
locality capable of producing such an effect, or of transporting masses of mineral
matter even as small as those under notice, there appears to me to be strong
evidence in favour of an offshoot of the Arctic current slowly moving downwards
between the Faroe Islands and Iceland.
I t has been calculated that an ordinary stream, running at the rate of no more
than 300 yards an hour, is capable of disintegrating and carrying away fine clay;
that a rate of 800 yards (or somewhat less than half a mile) an hour, will suffice
to transport coarse sand; whilst a current running a mile and a half, will roll
along rounded pebbles as large as a hen’s egg,—the inertia of stones of ordinary
specific gra-vity (that is, from 2-5 to 2*8) being reduced by more than a third on
their immersion in water. At extreme dearths, and in water surcharged under
an enormous pressure with saline matter, the inertia of masses of stone would be
still further reduced; and although a diminution of friction between them would
accompany this reduction, the general result would be materially infiuenced,
inasmuch as masses which could not otherwise have been dislodged would now
cooperate in the rolling action. This is a very material point, and one which I
cannot help thinking has been lost sight of, in a great measure, by those who
argue that, however strong a ciUTent may be, the lower stratum of water is so
retarded by friction against the bottom as almost enthely to lose its initial
velocity.
Supposing the bed of the sea to be perfectly level, the retardation would no
doubt talie place. But where very slight inclinations of the surface occur, so as
to allow fi’esh portions of the water to impinge on the sand or gravel, it will at
once be apparent that the primary force would at all events retain the greater
portion of its infiuence.
In the case of plateaus of moderate area, the sui-faces of which happen to be
raised above the general level of the sea-bed, and more especially if they have a
fall tending in the same direction as a deep-seated current, the entire force of the
latter would take effect in rolling and transporting stones, as well as in wearing
do\vn the surface.
I have stated that the sounding (No. 15 in the list) gives the greatest depth,
in the line from the Faroes to Iceland, about two-thirds of the way across, or, in
round numbers, about ninety miles to the eastward of Ingolfshofde. I t is a very