§ 7. CHRONOLOGICAL SYNOPSIS. 203 



the land, and its inhabitants. Two genera of marine reptiles, Ichthy- 

 osaurus and Plesiosaurus, swarmed in the Liassic and Oolitic ocean, 

 and their remains abound throughout the system. 



o. the triassic (Xew Red) formation. — A group 

 of variegated, blue, yellow, and red marls, abounding in 

 gypsum and salt ; with sandstones, limestones, and con- 

 glomerates, for the most part coloured red by peroxide of 

 iron. Fossils are not abundant, but some peculiar shells, 

 corals, crinoidea, reptiles, and coniferous plants, charac- 

 terize the series, which is of marine formation. 



Observations. — This group is the grand depository of rock salt in 

 England. In Germany the strata form a triple series (whence the name 

 Triassic) of variegated marls, limestones, and sandstones, which con- 

 tains peculiar fossil remains. The separation of these deposits from the 

 following has been made in consequence of certain genera and species 

 of animals, which abound in the more ancient rocks, being entirely 

 absent in the Triassic, and all the subsequent formations ; and also 

 from some genera, especially of Batrachian and other reptiles, appear- 

 ing for the first time in strata of this age. The Triassic is therefore, 

 at present, regarded as the lowermost, or base line, of the formations 

 comprised in the secondary epoch ; the faunas and floras of the older 

 strata being entirely distinct. 



IV. The Paleozoic Epoch. — Under this general 

 term are comprised all the ancient fossiliferous strata, the 

 organic remains of which, as the name indicates, belong 

 almost exclusively to species or genera that are wanting in 



all the newer formations. 



6. the permlax ( ' Magnesian Limestone) formation. — 

 A series of marine strata, consisting of limestones charged 

 with a large proportion of magnesia, red marls, conglome- 

 rates, and slates. These contain peculiar shells, fishes, and 

 reptiles. 



Observations. — This group of deposits was formerly named the Lower 

 J\ T ew Bed, or Magnesian Limestone; but, as either of these terms 

 is ambiguous, that of Permian (first suggested by Sir E. Murchison, 

 from the large development of the series in the ancient kingdom of 

 Perrnia in Russia) is now generally adopted. In this group are 



