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 





'^P 



'i^^ y' yf 





Fig. 181. — Globigerina ooze. 2J). (Murray and Renard.) 



heteropod shells, as Hyalea, Styliola, Spinalis, Atlanta, etc. 

 These shells also exist in considerable numbers in the deposits 

 around oceanic and other islands. 

 A globigerina ooze (Fig. 181) has 

 a 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 

 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.) 



^ They are PulvinuUna Menardii, cana- Murrayi and pelagica ; Orhulina universa ; 



riensis, crassa, Micheliniana, and tumida j Globigerina hulloides, cequilateralis, sac- 



Pullenia obliquiloculata ; Sphceroidina de- culifera (hirsuta), dubia, rubra, conglobata, 



hiscens ; Candeina nitida j Hastigerina and injlata. 



Fis 



182. — Globig-erina slab, oflF Alliga- 

 tor Reef. ] 47 fathoms. \^ . 



