OF TILGATE FOREST. 
283 
a new species of that genus. Among the gigantic 
vertebrae of Tilgate there are some which approacli 
in their general form to those of the plesiosauri ; 
but their bodies are concave on one side only, the 
other face being either flat, or slightly elevated ; 
the largest are above six inches in their longest 
diameter. 
Bones of Birds. — It is so rarely that the re- 
mains of birds are found in a fossil state, that, 
although a few mutilated bones are tlie only relics 
of these animals wliicli the strata of Tilgate have 
hitherto aflbrded, the fact is too remarkable to be 
passed by unnoticed. Vi, e have, in our collection, 
remains of three of the larger bones of the ex- 
tremities (either of the femur or tibia), of a wader 
larger than the common heron : they were sup- 
posed to be the bones of Pterodacfyles^ but M. Cu- 
vier, to whom they were shown in 1830, did not 
hesitate to determine that they belonged to a bird, 
probably a species of Ardea. 
In concluding this description of the organic 
remains of Tilgate Forest, we would repeat what 
we have elsewhere remarked, that the vast pre- 
ponderance of the land and freshwater exuviae 
over those of marine origin observable in these 
deposits, warrants the conclusion that the Wealden 
strata were formed by a very different agent to 
that which effected the deposition of the Portland 
beds below, and the sands and chalk abo\ e them. 
The seas, in the primitive ages of our planet, 
were inhabited by vast tribes of multilocular shells, 
which, however variable in their species, were not 
only of the same family, but also of tlie same ge- 
