Origin of Species Variorum

→ chanced to have 1859 1860 1861 1866 1869

OMIT 1872

→ So that, if such species 1866 1869

So that if such species 1859 1860 1861

Consequently if it 1872

→ any 1859 1860 1861 1866 1869

the deposition of any 1872

→ older and underlying 1869 1872

underlying 1859 1860 1861 1866

→ bed; 1859 1860 1869 1872

and older bed; 1861 1866

→ with 1859 1860 1861 1866 1869

by intermediate varieties with 1872

level during the process of deposition, which would

not

never even

have been

sus- pected,

suspected,

had not the trees →chanced to have been preserved:

thus,

thus

Messrs.

Sir C.

Lyell and

Dawson

Dr. Dawson

found carboniferous beds 1400 feet thick in Nova Scotia, with ancient root-bearing strata, one above the

other

other,

at no less than sixty-eight different levels. Hence, when the same species

occurs

occur

at the bottom, middle, and top of a formation, the probability is that

it has

they have

not lived on the same spot during the whole period of deposition, but

has

have

disappeared and reappeared, perhaps many times, during the same geological period. →So that, if such species were to undergo a considerable amount of modification during →any one geological

formation,

period,

a section would not

probably

....

include all the fine intermediate gradations which must on

our

theory have

existed,

existed

~~between them,~~

between them,

but abrupt, though perhaps

very

....

slight, changes of form.

It is all-important to remember that naturalists have no golden rule by which to distinguish species and varieties; they grant some little variability to each species, but when they meet with a somewhat greater amount of difference between any two forms, they rank both as species, unless they are enabled to connect them together by

the closest

intermediate

gradations;

gradations.

and

And

this,

this

from the reasons just

assigned,

assigned

we can seldom hope to effect in any one geological section. Supposing B and C to be two species, and a third, A, to be found in an →older and underlying →bed; even if A were strictly intermediate between B and C, it would simply be ranked as a third and distinct species, unless at the same time it could be

~~most~~

most

closely connected →with either one or both

forms.

forms

~~intermediate~~

intermediate

~~varieties.~~

varieties.

Nor should it be forgotten, as before explained, that A might be the actual progenitor of B and C, and yet

would

might

not

at all

....

necessarily be strictly intermediate between them