Origin of Species Variorum

↑ 1 blocks not present in 1859 1861 1866 1869 1872; present in 1860

But perhaps it would be safer to allow two or three inches per century, and this would reduce the number of years to one hundred and fifty or one hundred million years.

→ in all probability a far 1859

it is not improbable that a 1860

→ years! 1859 1860 1861

years! Now turn to our richest geological museums, and what a paltry display we behold! 1866

→ numbers of our 1859 1860 1861 1866 1869

very many 1872

of one inch per century for the whole length would be

a sufficient

an ample

allowance. At this rate, on the above data, the denudation of the Weald must have required 306,662,400 years; or say three hundred million years. ↑

The action of fresh water on the gently inclined Wealden district, when upraised, could hardly have been great, but it would somewhat reduce the above estimate. On the other hand, during oscillations of level, which we know this area has undergone, the surface may have existed for millions of years as land, and thus have escaped the action of the sea: when deeply submerged for perhaps equally long periods, it would, likewise, have escaped the action of the coast-waves. So that →in all probability a far longer period than 300 million years has elapsed since the latter part of the Secondary period.

I have made these few remarks because it is highly important for us to gain some notion, however

imper- fect,

imperfect,

of the lapse of

time.

years.

During each

~~of these~~

of these

year,

years,

over the whole world, the land and the water

have

has

been peopled by hosts of living forms. What an infinite number of generations, which the mind cannot grasp, must have succeeded each other in the long roll of →years! Now turn to our richest geological museums, and what a paltry display we behold!

the

Poorness

poorness

our

Palæontological

Collections .

collections .—

That our

~~palæontological~~

palæontological

collections are

~~very~~

very

imperfect

imperfect,

is admitted by every one. The remark of that admirable palæontologist,

~~the late~~

the late

Edward Forbes, should

never

not

be forgotten, namely, that →numbers of our fossil species are known and named from single and often broken specimens, or from a few specimens collected on some one spot. Only a small portion of the surface of the earth has been geologically explored, and no part with