STILL FOUND IN A LIVING STATE. 365 
to awaken a more general and active interest for this kind of in- 
quiry. I shall only draw such conclusions as are most obvious ; 
since the further we depart from actual observation, the more 
we deviate into the field of uncertain speculation, which when 
constructive, instead of being completive merely, becomes the 
very opposite of philosophical inquiry, and is just as feasible for 
anybody as for the philosopher himself. 1 would desire there- 
fore that my conclusions should always be less; rather than 
more, than the observations might warrant me to draw. 
1. There are numerous animals of the chalk or secondary 
formation of the earth which are still found living, and precisely 
such as do not, either from great variation of form within generic 
limits, or from the simplicity of their exterior, leave any uncer- 
tainty in determining their specific difference. 
2. Of the animal forms which constitute the greater mass of 
the white chalk, those which preponderate in number of indi- 
viduals are identical with living species ; and hitherto all the prin- 
cipal species which form the rocks have been observed alive even 
in the short time during which the inquiry has been proceeding. 
3. The principal number of species, and the great mass of 
individuals of these recent forms, are microscopic Infusoria and 
calcareous-shelled Polythalamia, scarcely or not at all perceptible 
to the naked eye, which nevertheless form so incalculably great 
a volume of the solid portion of the earth, that the few species 
asserted to be still living, from other groups of animals of 
higher organization, even if they were all decidedly identical, 
bear not the slightest comparison with the number and mass. 
4. The microscopic organisms are, it is true, far inferior in 
individual energy to lions and elephants ; but in their united in- 
fluences they appear far more important than all these animals. 
5. The fifty-seven recent species of the chalk in Europe, 
Africa and Asia do not live solely or principally in southern la- 
titudes, as has been shown with respect to the recent larger 
forms of the so-called Eocene formation, but have been observed 
living both in those and in northern latitudes. These recent 
species also are not rare nor isolated, but fill in incalculable 
numbers the seas of northern Kurope, and are not wanting on 
the tropical coasts of the American ocean. 
6. The idea that the temperature and constitution of the at- 
mosphere and oceans were essentially different at the period of 
the chalk formation, and adverse to the organized beings at pre- 
sent existing, naturally acquired more probability and weight 
