DENNIS, ON CETACEAN BONES. 
199 
tlie fifth edition of his ^ Manual of Elementary Geology/ of 
the discovery by Mr. Beckles^ in the Middle Purbeck Oolite, 
of about fourteen different mammifers; and it is worthy of 
notice that all these animals were of small size, the largest 
not exceeding a rabbit. Are we to suppose that no large 
mammifers were cotemporary with these living creatures, 
and may it not he just possibUy that in the Red Crag of 
Suffolk, exist the mammalian relics of cotemporaries of 
Stereognathus, of Spalacotherium, and Plagiaulax. The 
giving utterance to such an idea may, in the eyes of some, 
convict me of geological heresy ; but if we look a little into 
the facts of the case, it will perhaps not appear so imaginary 
as at first sight. The first question to consider is, did they 
belong to the Red Crag or Pliocene period? or, in other 
words, were the animals living about the time of that 
formation ? If so, supposing that inundations and rivers 
conveyed these once ponderous bones to the sea, and the sea 
then rolled them, they must have become fossilized after 
they were deposited in the Red Crag ; but, on the contrary, 
they show evidence of having been fossilized anterior to their 
having been rolled — they have still the gloss upon them 
that they acquired when they formed the shingle on the 
beach. They were veritable stones then; if they had not 
been so, all trace of the structure of bone would have been 
obliterated, whereas this structure is often marvellously pre- 
served. There must then have existed some deposit that 
once contained the fossils in a more perfect condition, and 
where they became petrifactions ; the older Tertiary beds 
in this country, with the exception of a cetolite and 
several cetacean fragments found in the London Clay, 
affording no clue as to their primary sepulture ; and sup- 
posing them to be the spoils of Eocene deposits, we have a 
right to expect to find them there in greater numbers and 
perfection. I cannot think, then, that the deposit to which 
they primarily belonged is anywhere developed in this 
country ; and they might have lived, for aught we know to 
the contrary, when Oolitic forest trees grew in Portland, and 
have trodden down beneath their feet tropical cycadites. If 
a rolled flint is picked up, though time has altered its 
outward appearance, there is no difficulty in determining 
whence it came, though we may not be able to follow 
it through all the journeys it has made since it became a 
h^ird substance ; and so the mineral characters of the Crag 
fossils seem to afford the best, perhaps the only clue to the 
time when they formed parts of living beings, and these cha- 
racters appear to agree with those of fossilized bone belonging 
VOL. V. s 
