THE VOYAGE OF H.M.S. CHALLENGER. 
IGG 
Sydney to New Zealand. — The two soundings in 2G00 fathoms contained respectively 
7 and 19 i)cr cent, of carbonate of lime. In 1975 fathoms there was 77 per cent., in 
1100 fathoms 84 per cent., and in 275 fathoms 8S per cent, (see Chart 27). The car- • 
bonatc of lime in all these consisted essentially of the shells of pelagic Foraminifera, with 
Coccoliths, Coccospheres, and Rhabdoliths. In the deeper deposits there is, it will be 
noticed, less and less carbonate of lime, and this is due to the gradual removal 
of tlie more delicate and smaller shells (see Diagram 11). While these small shells 
and Coccospheres made up most of the deposit at 275 and 400 fathoms, they were very 
rare at a depth of 2600 fathoms, though they appeared to be quite as abundant at the 
surface over the one locality as over the other. The mineral particles were very minute 
in these soundings, and consisted chiefly of felspars and glassy volcanic fragments. As 
tlie entrance of Cook Strait was approached, the mineral particles derived from the coast 
of New Zealand increased both in number and size, and the pelagic shells diminished, 
while glauconite, which was absent in the soundings from the middle of the section, 
again made its appearance. At 150 fathoms the deposit was a Blue Mud with 26 per 
cent, of carbonate of lime. 
Off New Zealand. — The deposits off the east coast of New Zealand in 1100 and 700 
fathoms (see Chart 27) were Blue Muds, with a thin characteristic layer of a reddish 
colour on the surface. They contained only from 4 to 10 per cent, of carbonate of lime, 
the chief part of the deposit consisting of amorphous and clayey matter and fine mineral 
particles derived from the neighbouring land. The mineral particles were uniform in 
size and nature in both localities, but while they were estimated at 21 per cent, in the 
former, in the latter deposit they made up 25 per cent. Siliceous organisms were few. 
The dredge brought up pumice stones at both stations. 
New Zealand to Tonyatahu. — The deposits off the Kermadec Islands in 520, 630, 
and 600 fathoms (see Chart 27 and Diagram 12) were Volcanic Muds, containing very 
many large blocks of pumice. A very large fragment of a huge new Hexactinellid 
Sponge, Poliopoyon yiyas, was brought up from 630 fathoms attached to pumice stones ; 
it mca.surcd about 2 feet by 3 feet 6 inches.^ The deposit at 2900 fathoms was a Bed 
Clay, which gave no trace of effervescence when treated with dilute acid, showing that 
it did not contain any carbonate of lime. The mineral particles were very small, the 
bulk of them being less than 0‘05 mm. in diameter, and consisted of felspar, magnetite, 
and hornblende ; there were, however, some large fragments of pumice, and the great bulk 
of the fine w.'ishings of the deposit was composed of very minute fragments of pumice. 
Cff Tonyatahn. — When outside a line joining Mallenoah and Atataa Islands dredgings 
were obtained, first in 18 fathoms, and then in 240 fathoms (see Chart 28). The deposit 
at both these depths was a Coral Sand containing from 86 to 90 per cent, of carbonate of 
lime, composed of fragments of Coral, calcareous Algae, Orhitolites and many other 
‘ C’l Ijy lO'C decijiietres. 
