&ILS. 69 



ie larger groups, such as in natural history arc 



termed I of Animals. Thus in the old slaty 



led Cambrian and Silurian the entire 



termed Graptolites is extinct. 



the primary rock is an extinct group of 



. which have the radiating 

 shelly partitions termed septa, in multiples of 

 small extinct groups of Echino- 

 ms in the Silurian and carboniferous ro 



allied • urchins, named Cystoidea and 



Ami >ng ( Irustacea th< the ex- 



• ips rrilobites, comprising more than 



fifty 1; and the Merostomata, compris 



animals wh allied to the k at)S and 



Other groups of animals, though not entirely 



much better represented in the fossil 

 te than in existing nature. M 5t • t the gen< 

 of tile groups Of lamp-shells named llrachiopoda, 



ind only in the Primary 

 and the larger number of allies of the Nautilus 



. partly in the primary, 

 and partly in tin iod ^( time. 



>f the existing groups of animals 

 date from note, if not from the earl 



known geologi [jes. The genera in which 



they st met with, frequently appear to ha 



persisted ever since, without under any ap- 



iable d md those minor modihra- 



hich distinguish species. Although the 



fruits of the Araucaria^ of various pines, and of 

 ire found in the lower - dary rocks, 

 it is not until the latter part of the secondary 

 period that any deposit yields enough fossil leaves 

 to enable the vegetation of the earth to be com- 

 pared as a group with living types. The common 



