256 THE FOEAMINIFEEA 



and species in the Carboniferous system. At this 

 period the Foraminifera were so abundant in certain 

 areas that they often formed very extensive deposits. 

 For example, Saccanimiiia constitutes a large pro- 

 portion of the rock known as the Saccammina lime- 

 stone of England, Scotland, Ireland, and Belgium ; 

 and this genus is found throughout the Carboniferous 

 series, but chiefly near its base. Fusiilina is 



Fig. 28. — Saccammina Limestone ; Carboniferous, 

 Northumberland, x Qh. Original. 



another important genus, forming the main bulk 

 of the Fusulina limestones so extensively developed 

 in the Upper Carboniferous of Russia, China, 

 Japan, and North America ; and which also occurs 

 in Spain (Cantabrian Chain) and the Southern 

 Alps (Upper Carniola and Carinthia), the Caucasus, 

 Isle of Chios, Borneo, and Sumatra. 



The two above-mentioned genera are of fairh' 



