36 



is of very great geological interest, since the embedded 

 remains give us some insight into the nature of the terres- 

 trial fauna and flora of the lower cretaceous epoch. Dr. 

 Fittoa first discovered that the whola group was of fluvia- 

 tde origin, and in proof of this he pointed out the entire 

 absence of marine foss'ls characteristic of the cretaceous 

 rocks above and of the oolitic strata below, and to the pre- 

 sence in the weald of paluJinae and various fluviatile shells, 

 as well as the bones of terrestrial reptiles, and the trunks 

 and leaves of land plants, including conifers, cycads, 

 palms, ferns, &o., which indicate a genial, if not a tropical, 

 climate. Geology brings us acquainted with strange 

 animals, as will be seen by the reptilian fauna, which was 

 rich, and comprised the iguauodon, megalosaurus, hyloeo- 

 saurus, ichthyosaurus, plesiosaurus, pterodactyl, and 

 chelonians or" tixrtles, of some of which my friend Mr. 

 Jones has kindly brought down portraits. In the upper 

 division, or weald clay, its highest beds are comformable to 

 the inferior strata of the lower greensand, and of similar 

 mineral composition. To exphin this. Sir Charles Lyell 

 says — we may suppose that, as the delta of a great river was 

 tranquilly subsiding, so as to allow the sea to encroach upon 

 the space previously occupied by fresh water, the river still 

 continued to carry down the same sediment into the sea. 

 In confirmation of this view it may be stated that the re- 

 mains of the Iguanodon mantcllii, a gigantic terrestrial rep- 

 tile, verv characteristic of the wealden, was discovered by Mr. 

 Bensted, in the overlying Kentish rag, or marine lime stone 

 of the lower greensand, near Maidstone. Hence we may in fer 

 thatsome of thesaurians, which inhabited the country of the 

 great river, continued to live when part of the country had 

 become submerged beneath the sea. Thus in our own times 

 we may suppose the bones of large alligators are frequently 

 entombed iu recent fresh water strata in the delta of the 

 Ganges. But if part of that delta should sink down so as 

 to be covered by the sea, marine formations might begin 

 to accumulate in the same space where fresh-water beds 

 had previously been formed ; and yet the Ganges might 



