INFUSORIA AND OTHER ANIMALCULE. 255 



a submarine deposit, consisting entirely of the 

 siliceous particles of which the skeletons of these 

 inferior beings are composed. This deposit is seen 

 on the shore of Victoria Land, and at the base of 

 the volcanic mountain Erebus. 



Samples ot water taken up by Schager to the 

 south of the Cape of Good Hope in 57 lat., and 

 again under the tropics in the Atlantic, show that 

 the ocean, in its ordinary condition, and without 

 any apparent discoloration, contains numerous mi- 

 croscopic living organisms. Ehrenberg has shown 

 that the infusorial beings now living nourish at 

 heights of 10,000 feet on land, far above the snow 

 level, and at depths of 10,000, 12,000, and 16,000 

 feet in the sea. In his recent work, " Mikro- 

 geologie," he has shown also that the most ancient 

 of the fossil Infusoria, whether belonging to the 

 Carboniferous or to the Silurian strata, belong to 

 the same genera, and often to the same species, as 

 those which actually exist at the present day; 



"The minute grains of greensand," says this 

 author, fc which are characteristic of many rocks, 

 have a different nature from the green earth often 

 met with in concretionary masses. The former, 

 from the Glauconie of the Paris limestone to the 

 Azoic lower Silurian greensand near Petersburg, 

 appear to consist of green opalescent casts of Poly- 

 ihalamia, composed of a hydro silicate of iron. The 



