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shows that 41,000 millions of fossil specimens of the Gaillonella 
distans are contained in a single cubic inch), without recognizing 
in such strata a perpetuation of countless generations ? Who, 
again, can take into review the vast superpositions of different 
strata on the same spot, indicating successive alternations of 
fresh-water deposits and deep-sea bottoms, subsidences and 
elevations, dislocations and denudations, arctic climates and 
tropical, with buried remains of the most divergent forms of 
flora and fauna, and not be convinced that all this must of 
necessity represent the gradual accretion of successive ages ? 
To say nothing of the old Cambrian and Silurian strata, almost 
devoid of organic life, the Old Red Sandstone, with its marvel- 
lous fossils, occupying a thickness in some places of 10,000 feet, 
the Carboniferous Coal-measures, which in South Wales are to 
be found 12,000 feet thick ; the Magnesian Limestones of the 
Permian period, the lower formation of which alone are 3,000 
feet in some parts of the north-west of England; the New 
Red Sandstone, again; and then the Oolitic beds, which in the 
Isle of Portland underlie a fresh-water deposit, that, too, under- 
lying a layer of old forest tree-stumps, and that once more 
underlying a bed of fresh-water calcareous slate ; — to say nothing 
of all these revolutions of the earth’s surface ; — who can study 
the fresh- water Clays of the Wealden in Sussex, Kent, and 
Surrey, succeeded by those deep-sea deposits of gault, green- 
sand, and chalk which surround, and in part overlie them ; and 
these, again, followed by the Lower Eocene beds of the London 
Clay, containing tropical plants, shells, and animals ; and these 
once more by further deposits distinctly evidencing a period of 
glacial action, and all ending in the tertiary crust above; — who, 
I say, can contemplate changes and revolutions like these, during 
which species of flora and fauna have lived and flourished in all 
sorts of varieties, each race displacing the other, without 
having an overwhelming sense both of the forces of nature, and 
of the enormous periods of time which must have been necessary 
to produce such accumulated results? 
10. The same conviction that extended cycles of ages must 
have passed away since the heavens and the earth were first 
created, is no less forced upon our attention by the discoveries 
of astronomy. I particularly refer to those immense periods 
which the passage of light can be demonstrated to require before 
it can reach the eye of an observer on the earth when it comes 
from stars situated in the Milky Way, or from the still more 
distant nebulse. 
11. So long, of course, as the distances of the fixed stars 
were unknown, it was utterly impossible to ascertain the length 
of time which their light would need in order to reach the 
