REPOKT ON THE DEEP-SEA DEPOSITS. 
151 
Off Bermuda . — During the two visits to Bermuda a number of soundings and 
dredgings were made around the islands and inside the reefs (see Chart 8). At a depth of 
200 fathoms, about 2 miles from the reefs, the deposit was composed of large fragments 
of Coral, Foraminifera, Echinoderms, Polyzoa, Molluscs, Algse, and concretionary lumps, 
some of which were 2 or 3 centimetres in diameter. At 380 fathoms, 3 miles from 
the reefs, the fragments were smaller, and, in addition to the above, there were many 
Pteropod and Heteropod shells. At 950 fathoms, 4 miles from the reefs, the particles 
were still smaller, and there was a considerable admixture of pelagic Foraminifera. 
At 1950 fathoms, 5 miles from the reefs, the deposit was a nearly pure Globigerina 
Ooze, made up chiefly of pelagic Foraminifera, with only a small proportion of 
species living on the bottom and fragments from the reefs. All these deposits 
contained from 81 to 93 per cent, of carbonate of lime. The residue, after treatment 
with dilute acid, consisted of a few siliceous spicules, of felspar, augite, magnetite, and 
glassy fragments. None of the mineral particles exceeded 0'07 mm. in diameter. At 
2650 fathoms, 30 miles from the reef, the deposit was a Globigerina Ooze, containing 
over 60 per cent, of carbonate of lime, and Eed Clay at still greater depths. The 
appearance of the deposits off the Bermudas, in depths of 200, 380, 950, and 1950 
fathoms, is represented in the four figures of Plate XIII., and these show a gradual 
change in the size and nature of the calcareous organic remains with increasing depth 
and distance from the islands, although the percentage of carbonate of lime remains 
nearly the same at all depths. 
Inside the reefs, in depths of 4 to 10 fathoms, there were Coral Muds and Sands, 
consisting for the most part of triturated fragments of calcareous Algge, Corals, Polyzoa, 
mixed with which were Foraminifera, Serpida, Gasteropods, and Lamellibranchs. These 
gave on analysis from 86 to 95 per cent, of carbonate of lime. A few Sponge spicules, 
imperfect casts of Foraminifera, and Diatoms were also present ; the mineral particles were 
few but relatively large, fragments of quartz and volcanic glass being the most abundant. 
Bermuda to Halifax . — The deposits between Bermuda and the coasts of North 
America (see Chart 9) showed, irrespective of depth, a regular decrease in the quantity 
of carbonate of lime as the American shores were approached. While over 50 per 
cent, of carbonate of lime occurred at 2600 fathoms, about 100 miles from Bermuda, 
in 1240 and 1250 fathoms, near the American shores, only 15 and 16 per cent, were 
found. The large pelagic Foraminifera made up the principal part of the carbonate of 
lime in the deposits around Bermuda, but they disappeared almost completely from the 
bottom when within the influence of the Labrador current. Rhabdoliths likewise 
disappeared from the bottom along with the larger tropical pelagic Foraminifera, while 
Coccospheres were found in the deposits under the Labrador current. The remains of 
siliceous organisms were uniformly though sparingly represented, with, however, specific 
differences in the cold and warm regions. 
