Origin of Species Variorum

→ those which do not change will 1859 1860 1861 1866

otherwise they would 1869 1872

→ long-enduring fossiliferous formations 1859 1860 1861 1866

long-enduring formations, 1869

enduring formations, rich in fossils, 1872

→ depends 1859 1860 1861 1866 1872

rich in fossils, depends 1869

→ areas whilst subsiding, 1859 1860 1861 1866

subsiding areas, 1869 1872

→ of time; consequently 1866 1869 1872

consequently 1859 1860 1861

→ progenitors. 1859 1860 1861 1866

progenitors, and organisms already differing would vary in a different manner. 1869

progenitors; and organisms already differing would vary in a different manner. 1872

→ our fantail-pigeons were all 1859 1860 1861 1866

all our fantail pigeons were 1869 1872

→ by striving during long ages for the same object, 1859 1860 1861 1866

OMIT 1869 1872

would

will

be liable to

....

exterminated.

extermination.

Hence we

~~can~~

can

see why all the species in the same region do at last, if we look to

long

wide

enough intervals of time, become

modified;

modified,

for →those which do not change will become extinct.

In members of the same class the average amount of change, during long and equal periods of time, may, perhaps, be nearly the same; but as the accumulation of →long-enduring fossiliferous formations →depends on great masses of sediment

being

having been

deposited on →areas whilst subsiding, our formations have been almost necessarily accumulated at wide and irregularly intermittent

intervals;

intervals

→of time; consequently the amount of organic change exhibited by the fossils embedded in consecutive formations is not equal. Each formation, on this view, does not mark a new and complete act of creation, but only an occasional scene, taken almost at hazard, in

an ever

slowly changing drama.

We can clearly understand why a species when once lost should never reappear, even if the very same conditions of life, organic and inorganic, should recur. For though the offspring of one species might be adapted (and no doubt this has occurred in innumerable instances) to fill the

~~exact~~

exact

place of another species in the economy of nature, and thus supplant it; yet the two forms— the old and the new— would not be identically the same; for both would almost certainly inherit different characters from their distinct →progenitors. For instance, it is

~~just~~

just

possible, if →our fantail-pigeons were all destroyed, that

fanciers

fanciers,

→by striving during long ages for the same object, might make a new breed hardly distinguishable from

the

our

present

breed;

fantail;

but if the parent rock-pigeon were