332 PROF. EHRENBERG ON ANIMALS OF THE CHALK 
gether in a small space, then a slight local change of the earth’s 
surface can destroy the whole mass, like other organisms; but 
if they become diffused over the earth by currents of the ocean 
and by the wind, then do we undoubtedly recognise a capability, 
denied to all shells and fish, &c. more confined to a certain cli- 
mate, of withstanding for an incalculable period the destroying 
influences of the earth’s surface, not merely as genus and species, 
but even as (only always partially reproduced) individual forms. 
A constant and close reflection on these discoveries which 
were long ago made by me, the results of which I have hitherto 
made only a partial and occasional mention of because I felt the 
necessity of first making myself still more confident as to them, 
has had much influence upon my subsequent labours in this 
branch of science; and if others are more disposed to pass by 
these considerations with indifference, it may, as usual, perhaps 
arise from this circumstance, that the subjects le remote from 
the previous circle of inquiry, and will then only obtain their 
natural interest when they shall have become clearly manifest. 
After having been constantly attaining a firmer basis, and a con- 
tinually increasing conviction of the reality of these views, I felt 
incited to further deductions and inferences. 
I first applied myself to the contradiction in my previous ob- 
servations upon the relation of the microscopic organisms, ac- 
cording to which there were found as the main mass of the chalk 
marls of Sicily and Oran, six genera of infusorial shells consist- 
ing of numerous species quite different from any of the pre- 
sent world, while in the same marls, and in the white chalk itself, 
I had gradually recognised six species of recent Infusoria. I con- 
cluded, therefore, that either the six recent Infusoria, together 
with the two to three small Terebratulz, which form exceptions 
to the more general law of nature indicated by the greater and 
supposed extinct forms of the fossil organisms of the chalk, are 
actually different from the recent; or that the previously un- — 
folded and other similar physiological properties render the 
smaller organisms especially and more than others capable of — 
longer duration, and of explaining several hitherto obscure geo- 
logical relations of general interest. 
III. Researches on Recent Animals of the Chalk Formation, and 
their results. 
The motives which I have thus stated, induced me, during 
the vacation, Sept. 1839, to visit the sea coast, in order to be | 
