go EXTINCT MONSTERS. 
Mrs. Mantell, in 1822, in the coarse conglomerate of certain 
strata in Tilgate Forest, belonging to the Cretaceous period (see 
Table of Strata, Appendix I.). Dr. and Mrs. Mantell subsequently 
collected a most interesting series of these remarkable teeth 
(which, fora time, puzzled the most learned men of the day), from 
the perfect tooth of a young animal, to the last stage, that of a 
mere long stump worn away by mastication. In external form 
they bore a striking resemblance to the grinders of herbivorous 
mammals, and were wholly unlike any that had previously been 
known. Even the quarrymen, accustomed to collect the remains 
of fishes, shells, and other objects embedded in the rocks, had 
not observed fossils of this kind ; and until Dr. Mantell showed 
them his specimens, were not aware of the presence of such teeth 
in the stone they were constantly breaking up for the roads. The 
first specimen that arrested his attention was a large tooth, which, 
from the worn surface of its crown, had evidently once belonged 
to some herbivorous animal. In form it so entirely resembled 
the corresponding part of an incisor tooth of a large pachy- 
dermatous animal ground down by use, that Dr. Mantell was 
much embarrassed to account for its presence in the ancient 
Wealden strata, in which, according to all previous experience, 
no fossil remains of mammals would be likely to occur. No 
reptiles of the present day are capable of masticating their food ; 
how, then, could he venture to assign it to areptile? Here was 
a puzzle to be solved, and in his perplexity he determined to try 
whether the great naturalist at Paris would be able to throw any 
light on the question. Through Sir Charles (then Mr.) Lyell, 
this perplexing tooth was submitted to Baron Cuvier ; and great 
was the doctor’s astonishment on hearing that it had been without 
hesitation pronounced to be the upper incisor of a rhinoceros! 
The same tooth, with some other specimens, had already been 
exhibited at a meeting of the Geological Society, and shown to 
Dr. Buckland, Mr. Conybeare, and others, but with no more 
satisfactory result. Worse than that: Dr. Mantell was told that 
