REPOET ON THE DEEP-SEA DEPOSITS. 
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contributing to the formation of a Pteropod Ooze, viz., the shells of lanthina, larval 
Gasteropods, and the remains of some of the more delicate shells of pelagic Foraminifera, 
Candeina nitida, for instance. In one or two soundings of less than 1500 fathoms 
far removed from land, the Pteropod, Heteropod, and other delicate shells here referred 
to, appear to make up fully 30 per cent, of the deposit. In all deposits near continents 
and islands, where tropical oceanic waters occupy the surface, they are more or less 
abundant, though not unfrequently their presence is completely masked by the large 
quantities of other matters making up the deposits. In consequence of this it arises that 
a Pteropod Ooze formed in shallow water far from land differs very widely from one 
formed near to a continental shore or around an oceanic island. In oceanic regions the 
deposit approaches in constitution to a Globigerina Ooze, being, however, more friable 
and granular, and less homogeneous and uniform, from the presence of these larger 
shells, but the mineral particles are the same as in a Globigerina Ooze from the same 
region. Near the coast line the Pteropod deposits resemble the terrigenous deposits 
in the large number of shore materials and organisms which enter into their composition, 
the mineral particles being to a great extent the same as in Blue Muds, Green Muds, and 
Volcanic Muds, or fragments from coral reefs and calcareous organisms from shallow water 
may make up a large part of the deposit. 
In the Tables of Chapter II. 13 samples of Pteropod Ooze are described. These range 
in depth from 390 fathoms at Station 24 to 1525 fathoms at Station 3, the average being 
1044 fathoms. 
2 are fi’om depths less than 500 fathoms. 
3 „ from 500 to 1000 „ 
7 „ „ 1000 „ 1500 
1 „ over 1500 „ 
The carbonate of lime ranges from 52'22 per cent, in 900 fathoms to 98'47 per cent, in 
1240 fathoms, and averages 79 '25 percent. In these samples it is estimated that the car- 
bonate of lime derived from pelagic Foraminifera averages 47T5 per cent, of the whole 
deposit, that from the bottom-living Foraminifera 3T5 per cent., and from the other organ- 
isms, including the Pteropods, Heteropods, and Coccoliths and Rhabdoliths, 28 ’95 percent. 
Globigerinidse, Pidvinulina, Pteropods, and Coccoliths are present in all cases (13), 
Miliolidse, Rotalidse, Echinoderm fragments, and Rhabdoliths (12), Textularidse, otoliths 
of fish, Gasteropods, Heteropods, and Ostracodes (11), Lageniclse and Lamellibranchs (10), 
Polyzoa (8), Dentalium and Coral fragments (4), Nummulinidse and Coccospheres (3), 
and Cirripeds, Alcyonarian spicules, and Cephalopod beaks each in one case. 
The residue left on removal of the carbonate of lime is red or brown in the majority 
of cases, while the deposit itself is white or dirty white in most instances. The average 
percentage of the residue is 2075, being complementary to the quantity of carbonate of 
lime present. 
(deep-sea deposits chall. exp. — 1890.) 
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