R.EPOET ON THE DEEP-SEA DEPOSITS. 
149 
Off Madeira. — The deposits about the Dezertas and Madeira (see Chart 4) were 
Volcanic Muds, with from 30 to 40 per cent, of carbonate of lime, consisting chiefly of 
pelagic Foraminifera, except in one instance in 670 fathoms, where there was a Calcareous 
Sand with 96 per cent, of carbonate of lime made up of fragments of shells. Corals, 
Polyzoa, &c. The mineral particles in the deposits were angular fragments of felspar, 
magnetite, lapilli, basaltic scoriae, and volcanic glass. 
Madeira to Tenerife. — One sounding in 1975 fathoms w^as taken between Madeira 
and Tenerife (see Charts 2 and 5); only a small quantity of material was obtained 
sufficient to indicate that the deposit was a Clobigerina Ooze. 
Around the Canary Islands. — A number of soundings were taken around and among 
the Canary Islands (see Chart 5). Like those off Madeira, the deposits were chiefly 
Volcanic Muds, the percentage of carbonate of lime varying from 10 to 45. The mineral 
particles were angular fragments of vesicular basalt, augite, sanidine, magnetite, olivine, 
and volcanic glass. 
Tenerife to Sombrero. — The character of the deposits in the section from Tenerife to 
Sombrero (see Chart 6) presented marked differences. All the deposits in depths less 
than 2600 fathoms contained over 50 per cent, of carbonate of lime, and for these the 
names Clobigerina and Pteropod Oozes have been adopted. Pteropod Ooze is confined to 
two deposits from depths of 1525 and 1420 fathoms, the former on the eastern, the 
latter on the western side of the section, in which very many Pteropod and Heteropod 
shells occurred; in 1420 fathoms the proportion of carbonate of lime was the greatest, 
being 80 ‘69 per cent. In 1525 fathoms fragments of a large dead Alcyonarian Coral coated 
with manganese peroxide, and attached to large manganese nodules, were obtained in the 
dredge. Only a few fragments of Pteropods were found in the Clobigerina Ooze ranging 
between 1890 and 2025 fathoms, the carbonate of lime in the Clobigerina Ooze being 
made up chiefly of the dead shells of pelagic Foraminifera. The Pteropod Ooze, however, 
contained all the pelagic Foraminifera, together with Pteropod and Heteropod shells. In 
depths greater than 2600 fathoms, the quantity of carbonate of lime decreased as the 
depth increased, and below 3000 fathoms there were only a few traces in the 
deposit. 
Siliceous organisms, such as spicules of Sponges, Eadiolaria, and Diatoms, were not 
abundant ; generally they did not appear to make up more than 1 or 2 per cent, of the 
whole deposit, with the exception of the two deposits at 1525 and 1420 fathoms, above 
referred to, where the proportion probably rises to from 6 to 20 per cent., owing to the 
large number of Sponge spicules. 
The mineral particles, which were mostly of volcanic origin, seldom exceeded O'lO mm. 
in diameter, and consisted of felspars, hornblende, augite, magnetite, glassy fragments, and 
palagonite. In the deposits from the eastern portion of the section there were numerous 
small rounded particles of quartz covered with limonite. These would appear to be mostly 
