MANUAL OF NATURAL HISTORY. 573 



ralized by pyrites. Among them we may notice the 

 reticulate mass of the genus Manon; the branching 

 Scyphia; the funnel-shaped Chenendopora; the tur- 

 binate Cnemidium ; and the bulbiform Siphonia. 



Among the few vegetable productions found in 

 the Chalk, we may mention the liliaceous genus 

 Clathraria, and Fucoides from the Glanconite or 

 fire-stone. 



VI. CLASS.— TERTIARY-FORMATIONS. 



This class consists of an extensive series of strata, 

 marine, lacustrine, fluviatile, and volcanic. The 

 remains of animals and plants abound, comprising 

 extinct and existing species of mammals, shells of 

 the river, lake, and land, and many types altogether 

 extinct. It comprehends all the deposits of marl, 

 clay, sand, and gravel, which occur above the 

 chalk. The creation of races of beings that now 

 people the surface of the globe had its commence- 

 ment in the epoch of these formations. The cities 

 of London and Paris are built on marine and 

 fresh-water beds, which have been deposited during 

 this era, in the form of vast basins ; the tertiary 

 strata are found also on the coast of Africa ; the 

 shores of the Mediterranean, in the form of num- 

 mulite limestone ; in Russia, on the level tract be- 

 tween the Baltic and the Northern Ocean ; in Asia, 

 near the Bay of Bengal ; in the east of North 

 America ; and in Equatorial America ; they occur, 

 also, in the soft sandstones of the Swiss lakes ; the 



