328 
ELEMENTS OF GEOLOGY. 
Professor Owen has proposed the name of Galestes for the 
largest of the mammalia discovered in 1858 in Purheck, 
equalling the polecat (Mustela putorius) in size. It is sup¬ 
posed to have been predaceous and marsupial. 
Between forty and fifty pieces or sides of lower jaws with 
teeth have been found in oolitic strata inPurbeck; only five 
upper maxillaries, together with one portion of a separate 
cranium, occur at Stonesfield, and it is remarkable that with 
these there were no examples in Purbeck of an entire skele¬ 
ton, nor of any considerable number of bones in juxtaposi¬ 
tion. In several portions of the matrix there were detached 
bones, often much decomposed, and fragments of others ap¬ 
parently mammalian; but if all of them were restored, they 
would scarcely suffice to complete the five skeletons to 
which the five upper maxillaries above alluded to belonged. 
As the average number of pieces in each mammalian skele¬ 
ton is about 250, there must be many thousands of missing 
bones; and when we endeavor to account for their absence, 
we are almost tempted to indulge in speculations like those 
once suggested to me by Dr. Buckland, when he tried to 
solve the enigma in reference to Stonesfield: The corpses,” 
he said, “ of drowned animals, when they float in a river, dis¬ 
tended by gases during putrefaction, have often their lower 
jaw hanging loose, and sometimes it has dropped off*. The 
rest of the body may then be drifted elsewhere, and some¬ 
times may be swallowed entire by a predaceous reptile or 
fish, such as an ichthyosaur or a shark.” 
As all the above-mentioned Purbeck marsupials, belong¬ 
ing to eight or nine genera and to about fourteen species, in¬ 
sectivorous, predaceous, and herbivorous, have been obtained 
from an area less than 500 square yards in extent, and from 
a single stratum not more than a* few inches thick, we may 
safely conclude that the whole lived together in the same 
region, and in all likelihood they constituted a mere fraction 
of the mammalia which inhabited the lands drained by one 
river and its tributaries. They afibrd the first positive proof 
as yet obtained of the co-existence of a varied fauna of the 
highest class of vertebrata with that ample development of 
reptile life which marks all the periods from the Trias to 
the Lower Cretaceous inclusive, and with a gymnospermous 
flora, or that state of the vegetable kingdom when cycads 
and conifers predominated over all kinds of plants, except 
the ferns, so far, at least, as our present imperfect knowledge 
of fossil botany entitles us to speak. 
The annexed table will enable the reader to see at a glance 
how conspicuous a part, numerically considered, the mamma¬ 
lian species of the Middle Purbeck now play when compared 
