CHAP. V.] THE GULF-STREAM. 333 
already been so carefully and admirably investigated by the 
United States Coast Surveyors, except possibly by tracing the 
relation of the deeper layers of water beneath the stream with 
the layers at similar depths in other parts of the ocean. 
We steamed out of the Camber on the morning of the 21st 
of April, and, going through the narrows, took a series of 
soundings following as nearly as possible the hundred-fathom 
line. The bottom falls off very suddenly along the eastern and 
northern coasts. We got a sounding in the afternoon, Gibbs’s 
Hill Light-house 2° E. 182? miles distant, in 1375 fathoms; the 
bottom temperature was 3° C., and the bottom a fine gray mud, 
with a few foraminifera. On the following day we proceeded 
outside the reefs to the westward and southward, and sounded 
successively in 2450, 2100, and 1950 fathoms, finding in each 
case a bottom of gray mud, chiefly the detritus of coral with a 
scanty sprinkling of foraminifera, and a bottom temperature of 
1°-6 C. In the evening we sounded in 32 fathoms about 13 
miles to the south-west of Bermudas: this is a bank well known 
to the Bermudas fishermen, and is said to have been discovered 
from a large number of fish swimming near the surface. We 
anchored on the bank, and the fishing-lines were soon out, but 
we were very unfortunate, for only one or two “snappers” 
were taken. Early on the morning of the 23d, the surveying 
boats left the ship to sound out the bank; it was cold, blus- 
tering, unpleasant weather, with a falling barometer and rising 
wind. During the day we sent the jolly-boat away to lower 
the small dredge a couple of hundred yards or so from the 
ship; the dredge was then slowly dragged to the ship by the 
donkey-engine. The bank, which seems to be about five miles 
across, consists mainly of large rounded pebbles of the sub- 
stance of the Bermudas “Serpuline reef.” There is an abun- 
dant growth all over the pebbles of the pretty little branching 
corals Madracis asperula (Fig. 88), and MM. hellana ; and other 
invertebrates were abundant, particularly one or two large star- 
I.—22 
