594 FOSSIL PLANTS OF DIFFERENT STRATA. 



earliest fossil remains, including what have been called Transition, 

 Primary fossiliferous, and Grauwacke rocks, and extending up to the 

 Magnesian Limestone, immediately above the Coal measures. 2. 

 Secondary, extending to the chalk. 3. Tertiary, extending to the 

 recent deposits. The following tabular view is given by Ansted : 



I. Palaeozoic 



Older Palaeozoic Lower and Upper Silurian. 



Middle Palaeozoic Devonian and old Red Sandstone. 



( Carboniferous system, Lower new Red Sand- 

 Newer Palaeozoic < stone, and Magnesian Limestone or Permian 



{ System. 

 II. Secondary. 



Older Secondary Upper new Red Sandstone or Triassic System. 



Middle Secondary Liassic, Oolitic, Wealden. 



Newer Secondary Cretaceous. 



III. Tertiary. 



Lower Tertiary, or Eocene group. 

 Middle Tertiary, or Miocene group. 

 Newer Tertiary, or Pliocene group. 

 Superficial Deposits, or Pleistocene group. 



1176. Fossil Plants in different Strata. The plants in these strati- 

 fied rocks are either of a marine, fluviatile, lacustrine, or terrestrial 

 nature, according to the state of the globe at the period of their 

 deposition. The condition of the strata as regards fossils may de- 

 pend in some measure on the depth at which they were deposited 

 under the waters of the globe ; for Forbes finds that in the present 

 ocean, there is, at a certain depth, a zero of animal, and probably of 

 vegetable life. The state of preservation depends much on the nature 

 of the plant in regard to its anatomical structure. Cellular plants, 

 which are easily destroyed, have in a great measure disappeared, while 

 plants which resist well the decomposing action of water and other 

 agents, such as ferns, occur in great abundance. In the Silurian 

 system, the fossils consist chiefly of .invertebrate animals. Lignite has 

 been detected by Hugh Miller in the old Red Sandstone of the north, 

 and has been referred to some coniferous plants by Nicol. In the 

 Carboniferous system, fossil plants occur in vast quantity. With the 

 Palasozoic series one great epoch in the Rock formations was con- 

 cluded, and a change took place so as to usher in the Secondary series. 

 In the new. Red Sandstone, the fossil remains are few and local, while 

 in the Oolitic and Cretaceous systems they are more numerous. With 

 the Secondary series of strata a general condition of the globe ended, 

 and a new one commenced with the Tertiary strata. In these we 

 meet with fossil remains nearly resembling or identical with the exist- 

 ing races. The names given to the groups indicate this. In the 

 Eocene group (bus, dawn or morning, and X.BUVO;, new) we meet with 

 a certain proportion of living shells. In the Miocene (p.tiuu, less) the 

 number of living species increases, although still less in number than 





