224 Successive Geological Development. 



cotyledons, such as the Liliaceae and Palms, occur. In the 

 inferior oolite of England, we find the fruit of Podocarya, so 

 well described and illustrated by Dr Buckland in his Bridge- 

 water Treatise, and which seems clearly to have been an 

 endogen closely allied to the Pandanus or Screw Pine. 



In the strata from the triassic to the Purbec inclusive, 

 comprising Brongniart's age of gymnosperms, plants of the 

 family of Zamia and Cycas, together with ConifersB, predo- 

 minated in Europe far more than anywhere now on the globe 

 in corresponding latitudes. They must have given to the 

 flora of this period a peculiar aspect, but our data are too 

 scanty to entitle us to affirm that the vegetation of this 

 second epoch was on the whole of a simpler organization 

 than that of our own times. In Bronn's catalogue 223 species 

 only of plants are enumerated in all the rocks ranging from 

 the lias to the middle oolite inclusive. Not a few even of 

 these are referred to Algae, 29 species of that tribe having 

 been obtained from the lithographic slate of Solenhofen and 

 the neighbourhood, all from one subdivision of the oolite. 



The cretaceous strata are classed by Brongniart together 

 with the tertiary in the last of his three periods before al- 

 luded to, namely the age of angiosperms. The two upper divi- 

 sions of the Wealden, the Hastings sand and Weald clay, 

 may probably, for reasons to which I shall allude in the 

 sequel, be referred to the same age. In regard to the rocks 

 ranging from the lower greensand to the Maestricht beds 

 inclusive, they are chiefly marine, and we have theref(5re as 

 yet but little information respecting the contemporary plants 

 which grew on the land, but such as are known display a 

 transition-character between the vegetation of the secondary 

 and that of the tertiary formations. Coniferse and Cycadese 

 still continued to flourish, and even a tree-fern has been de- 

 tected in the ferruginous sand of the lower cretaceous group 

 in the Ardennes in France. Yet this vegetation is referred 

 by Brongniart to the age of angiosperms, some well-marked 

 leaves of dicotyledonous trees having been found in Germany, 

 in the cretaceous quader-sandstein and planer-kalk. The co- 

 existence of these with numerous cycads and with the great 

 reptiles, the Iguanodon, Ichthyosaurus, Plesiosaurus, and 



