S3 6 



THE POPULAR SCIENCE MONTHLY. 



Neotropical region is not only distinguished as the headquarters of 

 the Phyllostomidce, but also by being altogether destitute of the fly- 

 ing-foxes and Rhlnolophidae. 



Such being the relation of bats to space their geographical dis- 

 tribution what are their relations to time their geological distri- 

 bution ? 



I assume that my readers are acquainted with the fundamental 

 facts and laws of geology, and know that the successive layers, of 

 which the superficial crust of the earth is in very various degrees com- 

 posed, are classifiable into three sets : 1. The Primary or Palaeozoic 

 rocks ; 2. The Secondary or Mesozoic rocks (from the Trias to the 

 Chalk inclusively) ; and, lastly, 3. The Tertiary or Cainozoic rocks, 

 extending upward from the Chalk to the present day. 



Fig. C Flying-Fox (Pteropus Whittwei). 



Remains of beasts more or less closely resembling some of those 

 existing now in Australia are found low down in the secondary rocks, 

 namely, in the Triassic and Oolitic formations. Generally speaking, 

 however, beasts such as those which now exist are not found deeper 

 than the Tertiary strata, and this is the case with bats. 



The oldest fossil bat yet known is represented by a few teeth 

 found in Eocene deposits in Suffolk. The oldest perfect fossil bat is 

 the Vespertilio Parisiensis of the gypsum-bed of Montmartre, near 

 Paris. 



Some forms of existing beasts, however, which are now distinct 

 enough, such as the ox and the pig, or the tapir and the horse, were 



