STILL FOUND IN A LIVING STATE. 367 
9. Since now Polythalamia, and other forms identical with 
chalk animals, exist which are not endowed with spontaneous 
division, this faculty of the Infusoria, and their general nature, 
are not the sole causes to which the indefinite duration of the 
species is owing. 
10. In consequence of the mass-building Infusoria and Poly- 
thalamia, the secondary formations can now no longer be di- 
stinguished from the tertiary ; and in accordance with what has 
been above stated, masses of rock might be formed even at the 
present time in the ocean, and be raised by volcanic power above 
the surface, the great mass of which would, as to its constitu- 
ents, perfectly resemble the chalk. Thus then the chalk re- 
mains still to be distinguished by its organic contents as a geo- 
logical formation, but no longer as a species of rock. 
11. The power so conspicuous in the organic beings under 
consideration is, according to experience, so immensely great, 
even in its influence on the inorganic, that with the concurrence 
of favourable circumstances they alone might give rise to the 
greatest changes in the distribution of the solid of the earth in 
the shortest space of time, especially in the water; and the 
ascertainable extent of such influences, however great, remains 
constantly small in comparison to those that are possible, con- 
sequently do not give by their magnitude any certain measure of 
periods of time. 
12. The correctness of the above expositions is not founded 
on individual opinion formed from hasty inspections of petty 
objects ; but the microscopic objects on which the opinions are 
based (though fading from our notice as individuals, yet by 
their number forming mountains and countries) are accessible 
to any comparison in distinct preparations, made according to 
the methods already described; and almost all the forms here 
mentioned, especially all the more important ones, have been 
carefully preserved by me, and laid before the Academy. 
13. Thus then there is a chain, which though in the individual 
it be microscopic, yet in the mass a mighty one, connecting the 
organic life of distant ages of the earth, and proving that it is 
not always the smaller or most deeply lying which is the base and 
the type of those which are larger and nearer the surface on our 
earth; and moreover, that the dawn of the organic nature co- 
existent with us, reaches further back into the history of the 
earth than had hitherto appeared. 
