INTRODUCTION. Xlll 



in the present work, we will proceed to a general sketch of 

 Wealden palaeobotany. 



In the early part of the present century the "Wealden series of 

 Southern England was examined by Mantell and Fitton, and it 

 is mainly to their labours that we owe our earliest knowledge of 

 the life of that period. Gideon Mantell in 1822 published a 

 work on " The fossils of the South Downs, or Illustrations of 

 the Geology of Sussex," and included those rocks to which the 

 term Wealden is now applied under the so-called Greensand 

 formations, which he subdivided thus 1 : 



Iron Sand. 



Greensand formation 



Tilgate beds. 



Weald or Oak Tree clay. 



Greensand. 



In the first of these subdivisions plant remains are recorded, 

 but without any definite names, descriptions, or plates. The first 

 figures and scientific names of Wealdeu plants are those contained 

 in a paper contributed to the Transactions of the Geological Society 

 in 1824. Two members of the Council, Messrs. Stokes and Webb, 

 were appointed to describe certain fossils which had been forwarded 

 to the Society by Mantell from Tilgate Forest ; in the description 

 of the plants " invaluable assistance " was received from Mr. 

 Robert Brown. The following species are mentioned, with 

 figures 2 : 



Pecopteris reticulata, S. and W. = 

 Weichselia Mantelli (Brong.). 



Endogenites erosa, S. arid "W. = 

 Tempskya Schimperi, Corda. 



Clathraria anomala, S. and W. 

 Carpolithus Mantelli, S. and W. = 



? Equisetites Burchardt, Dunk. 

 Hymenopteris psilotoides, S. and "W. = 



Onychiopsis Mantelli (Brong.). 



In 1833 Mantell's work appeared on "The Geology of the 

 South-East of England," and in chapter xi. there is a " description 

 of the organic remains of the Wealden, and particularly of those 

 of the strata of Tilgate Forest." 3 The specific name of the 

 genus Clathraria is changed from anomala to Lyelli, Hymenopteris 

 psilotoides is spoken of as Sphenopteris Mantelli, Brong., Pecopteris 



1 p. 22. 



2 Trans. Geol. Soc. ser. ii. vol. i. 1824, p. 421. 



3 p. 232. 



