GIANT LAND REPTILES OR DINOSAURS. 113 



series of folds, is considerably older than the chalk, 

 from which it is separated by the beds known as the 

 Upper Greensand, Gault, and Lower Greensand, and is 

 collectively known as the Wealden series, or formation. 

 Instead of having been formed, like the overlying chalk 

 and other deposits, at the bottom of an ancient sea, 

 the whole of the Wealden beds are of purely fresh- 

 water origin a circumstance abundantly proved by 

 the fossils found in the beds themselves, which com- 

 prise fresh-water shells, and the remains of land plants 

 and land animals, to the total exclusion of all marine 

 organisms. It is, indeed, probable that the area of the 

 Wealden strata, which originally extended from Kent 

 to the Isle of Wight, once formed the delta of a mighty 

 river, flowing into the North Sea, and draining a very 

 considerable portion of Northern Europe, during that 

 period of the Secondary epoch of the geological scale 

 immediately preceding the one in which the greensand 

 and chalk were deposited. 



Apart from its many other points of interest to the 

 geologist, as well as those which it presents to the 

 botanist and the archaeologist, the Wealden area has 

 an especial and unique claim on the attention of the 

 palaeontologist. It was, indeed, mainly from the huge 

 fossil bones obtained during the earlier decades of the 

 present century from these deposits, by the late Dr. G. 

 A. Mantell, of Lewes, that our first definite knowledge 

 was acquired of that wonderful group of extinct land 

 reptiles forming the subject of the present chapter. 

 These creatures, for which Sir K. Owen has proposed 



