INTBODUCTIOtf. XIX 



This makes a total of 45 forms, of which the numbers in the 

 respective groups are as follows : 1 Thallophyte ; 2 Filicales ; 

 9 Cycadophyta ; 27 Conifers ; 5 Angiosperms. The proportions 

 of the representatives of the different groups are noticeably 

 different from those in most described floras : the extreme 

 scarcity of ferns and the overwhelming preponderance of 

 Conifers being unusual features in Mesozoic floras ; while, in 

 those vegetations which contain authentic Angiosperms, they 

 generally bulk more largely in the lists than in the present case. 



As the Lower Greensand flora has hitherto been merged with 

 that of the Wealden, it must first be compared with it. 



The recent additions to the Wealden Flora are included in a 

 complete summary by Prof. Seward (1913), and the total flora 

 brings the number of species up to 68 (with one or two other 

 fragments and incertce sedis). Of these a total of 32 are 

 Thallophyta to Pteridophyta, which include 23 species of ferns, 

 as against the two species of ferns in the Lower Greensand. 

 There are also 19 species of Cycadophyta, the rest of the flora 

 being composed of Conifers and gymnosperinic incertce sedis. 



Among the Conifers, 4 species represent the Araucarinene, 

 1 the CupressineEe, 5 the Abietine&, and the rest are uncertain. 



Not only is it true, as Seward (1895, p. 240) says, that 

 " we search in vain among the abundant samples of the Wealden 

 vegetation for any fragments of monocotyledonons or dicoty- 

 ledonous plants," while in the Lower Greensand the dicotyledons 

 are represented by five distinct and well-preserved genera ; but 

 " looking at the Wealden plants collectively, we notice a very 

 striking agreement with the flora of the underlying Jurassic 

 strata, and it would be difficult to point to any well-marked 

 or essential difference between the plant-life of the two periods. 

 The evidence of palaeobotany certainly favours the inclusion of 

 the Wealden rocks in the Jurassic series." 



Berry (1911, p. 101) writes : " As transitional deposits the 

 Wealden may well be partly of Jurassic age, but of late years 

 it has come to be accepted as a non-marine facies of the Neo- 

 comian, since, where it is present, the lowest marine beds of 

 the Neocomian are said to be absent. That the flora (Seward, 

 Ward) and fauna (Smith Woodward, Marsh) are Jurassic in 

 type is not to be wondered at, indeed, it would be remarkable 



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