SUBMARINE DEPOSITS. 265 
comprise over ninety per cent of the deposit. A pteropod ooze 
(Fig. 180) is met with in depths of less than two thousand fath- 
oms in the tropics, and is very largely made up of pteropod and 
Fig. 181. — Globigerina ooze. 20. (Murray and Renard.) 
heteropod shells, as Hyalea, Styliola, Spirialis, Atlanta, ete. 
These shells also exist in considerable numbers in the deposits 
around oceanic and other islands. 
A globigerina ooze (Fig. 181) has 
а much wider distribution in lati- 
tude than a pteropod ooze, and 
is met with in deeper water. It 
consists of vast numbers of the 
shells of various species of forami- 
nifera.' Some of the species pre- 
dominate in one locality, and some 
in another. "There are a large 
number of other species of fora- 
minifera in the deposits, but those Fis. 182. — Globigerina slab, off Alliga- 
tor Reef. 147 fathoms. 15. 
named make up more than ninety 
per cent of those present. They live in the surface waters, and 
their dead shells accumulate on the bottom, while the other 
species live on the bottom itself. (Fig. 182.) 
1 They are Pulvinulina Menardii, cina- Murrayi and pelagica ; Orbulina universa ; 
riensis, crassa, Micheliniana, and tumida ; Globigerina bulloides, œquilateralis, sac- 
Pullenia obliquiloculata ; Sphæroidina de- — culifera (hirsuta), dubia, rubra, conglobata, 
hiscens ; Candeina nitida ; Hastigerina and inflata. 
