1898 - 99 .] Soundings obtained by s.s. ‘ Britannia .’ 415 
per cent, of carbonate of lime, which continues through the Wind- 
ward Passage in depths down to 1800 fathoms, but is replaced 
again in deep water (over 2000 fathoms), between the north- 
ern coast of Haiti and Caicos Bank, by Blue Mud, containing 
5 or 10 per cent, of carbonate of lime. A very peculiar sample 
comes from this locality, containing an extraordinary proportion 
of volcanic mineral particles, and therefore called a Volcanic Mud 
(see description of Ho. 49, 2293 fathoms). On approaching the 
southern entrance of Turk’s Island Passage, in the neighbourhood 
of a reported danger called Fawn Shoal, which was unsuccessfully 
searched for in 1880 by H.M.S. ‘ Fantome,’ Pteropod Ooze, with 
about 90 per cent, of carbonate of lime, again covers the bottom in 
depths between 250 and 300 fathoms. The four samples are 
peculiar in that they contain internal casts of Foraminifera, Ptero- 
pods, and other organisms, these casts being composed of carbonate 
of lime, and not of a silicate as is usually the case ; similar casts 
were observed in the deposit collected by the ‘ Challenger ’ off 
Raine Island in Torres Strait (see detailed description further 
on). Off Turk’s Islands the deposit is Coral Mud or Sand, with 
80 to 90 per cent, of carbonate of lime, in depths less than 1000 
fathoms. From the steep slope to the north of Turk’s Island, in 
depths between 1000 and 2000 fathoms, no deposit-samples were 
brought home ; but in depths slightly over 2000 fathoms Globi- 
gerina Ooze, with 60 to 70 per cent, of carbonate of lime, was met 
with, succeeded by Red Clay containing about 3 to 15 per cent, of 
carbonate of lime in depths approaching and exceeding 3000 
fathoms, which continues until the bottom gradually shoals on 
approaching Bermuda, the percentage of carbonate of lime in- 
creasing to 20 and 25 per cent., the deposit insensibly passing 
into Globigerina Ooze with from 30 to 70 per cent, of carbonate 
of lime in depths between 2162 and 2562 fathoms, with Ptero- 
pod Ooze, containing 80 or 85 per cent, of carbonate of lime, 
nearer the shores of Bermuda in 1000 and 1395 fathoms. 
This series of soundings modifies somewhat the distribution of 
deep-sea deposits as laid down in this region on the chart 
accompanying the Challenger Report on Deep-Sea Deposits, 
published in 1891. Thus: — 
