724 



FOSSIL GENEKA AND SPECIES. 



27. Permian. Permian. 



28. Coal Measures. t r- ■,. -j, 



29. Carboniferous limestone. / Car-bomferous. 



30. Upper ; 

 > Devonian. 



31. Middle 



32. Lower 



33. Upper 



34. Lower 



Silurian. 



86'. Lower | Cambrian. 



37. Upper 



38. Lower 



Laurentian. 



Devonian. 



Silurian, 



Cambrian. 



Laurentian. 



Primary 



or 



Palaeozoic. 



Palaeozoic. 



The plants fomid in different strata are either terrestrial or aquatic, 

 and the latter exhibit species allied to the salt and fresh water 

 plants of the present day. Their state of preservation depends much 

 on their structure. Cellular plants have probably in a great measure 

 been destroyed, and hence their rarity ; while those having a woody 

 structure have been preserved. The following enumeration has been 

 compiled from Schimper's Traits de PaUontologie VSgUale. It is only 

 an approximation to the number of fossil plants described in the 

 various formations, as it includes many species said to be doubtful, 

 and many which are known merely by fragments of stems, or leaves, 

 fruits, etc. — ^the affinity of which cannot be accurately determined at 

 present : — 



Silurian . . . 17 



Devonian . . . 57 



Carboniferous Limestone 146 



Coal-measures . . 666 



Permian, 1 

 Magnesian Limestone, and '238 



Lower Red Sandstone, \ 



Triassio ... 93 



Jurassic 



Cretaceous 



Eocene 



Miocene 



Pliocene 



Total 



510 

 236 

 586 

 2467 

 215 



5131 



The following is a general statement of the number of fossil genera 

 and species belonging to the different classes and sub-classes of the 

 vegetable kingdom :• — 



DicoTYLEDONES — ^Dialypetalse 



Gamopetalse 



Apetalae Angiospennese 



Gymnospermeae 



MoNOCOTYi/EDONES — Petaloidese 



Glumiferse 



AooTTLEDONES — Acrogeuse 

 Thallogenae . 



740 



6131 



