12 BAT-TRIBE. 
teeth of a very small insectivorous Mammal, somewhat re- 
sembling those of a Bat, have been found in the Eocene sand 
at Kyson.* But the most numerous and authentic remains 
of the small species of the Cheiropterous order have been 
met with in England in the limestone caverns contaiming 
the fossil bones of extinct Bears, Hyznas, &e. In these 
situations, however, as likewise in the cave of Kostritz in 
Germany, the Bat’s bones occur mixed with those of existing 
as well as of extinct animals, and may, therefore, have 
been introduced at a recent period. 
The chemical condition of such small and delicate re- 
mains cannot be relied upon as evidence of their antiquity, 
since they are altered by surrounding agencies, and espe- 
cially by contact with calcareous stalactite, more rapidly 
than are the bones of larger quadrupeds. We must pause, 
therefore, before we adopt the conclusion at which Dr. 
Schmerling has too hastily arrived, that the skulls and 
other bones of Bats, which have lost a greater or less pro- 
portion of their animal matter, are coeval with those of the 
large extinct spelean or cave-haunting quadrupeds in the 
same absorbent state, which are associated with them. 
With regard to the more satisfactory test of the com- 
parison of Cheiropterous remains with the skeletons of exist- 
ing species, I have failed to detect in the more complete 
skulls and skeletons from cave localities any character by 
which they could be distinctly referred to unknown species 
of Bats, or to such as do not now exist in England: and 
after much pains bestowed on the less complete and more 
abundant fragmentary and detached parts of the enduring 
framework of the Cheiroptera, I have been seldom able,— 
partly, mdeed, from the still imperfect state of the Osteology 
of this Order,—to arrive at any sound specific determina- 
tions. 
* Annals of Natural History, 1839, p. 194. 
