VI PREFACE. 



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 palseobotany certainly favours 

 the inclusion of the Wealden rocks in the Jurassic series." 

 Mr. Arthur Smith Woodward informs me that the fishes of 

 the Wealden beds bear testimony to the same Jurassic alliance. 

 We are thus led to conclude that whereas the palseonto- 

 logical evidence, derived from the more purely marine 

 deposits, would induce us to place the Wealden beds with 

 the overlying and newer Cretaceous series the peculiar 

 estuary, or lake conditions, of these mostly fresh-water 

 deposits, full of remains of terrestrial organisms, both 

 of plants and animals, would, by their close relationship 

 with the underlying and older Purbecks and Oolites, fix 

 a Jurassic date to this ancient land surface upon which 

 the Wealden flora once flourished. 



HENRY WOODWARD. 



GEOLOGICAL DEPARTMENT, 



BRITISH MUSEUM (NATURAL HISTORY), 

 CROMWELL ROAD, S.AV. 



November IGth, 1895. 



