Origin of Species Variorum

→ probably 1859 1860

highly probable that 1861 1866

probable 1869 1872

→ those which have 1859 1860 1861 1866

that those which have 1869

that those which 1872

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

It is a more important consideration, clearly leading to the same result, as lately insisted on by Dr. Falconer, namely, that the periods during which species have been undergoing modification, though very long as measured by years, have probably been short in comparison with the periods during which these same species remained without undergoing any change.

→ in the case of 1859 1860 1861 1866 1869

with 1872

→ effected by palæontologists. 1859 1860 1861 1866 1869

done. 1872

→ OMIT 1860 1861 1866 1869 1872

CHAP. IX. GEOLOGICAL RECORD. 1859

→ only 1859 1860 1861 1869 1872

distinct species from their European representatives, and by other conchologists as only 1866

→ only by the future geologist 1859 1860 1861 1866 1869

by the future geologist only by his 1872

→ seems to me 1859 1860

is 1861 1866 1869 1872

confined to some one spot. Most marine animals have a wide range; and we have seen that with plants it is those which have the widest range, that oftenest present varieties; so

that,

that

with shells and other marine animals, it is →probably →those which have had the widest range, far exceeding the limits of the known geological formations of Europe,

~~which~~

which

have oftenest given rise, first to local varieties and ultimately to new species; and this again would greatly lessen the chance of our being able to trace the stages of transition in any

ony

one

geological formation. ↑

It should not be forgotten, that at the present day, with perfect specimens for examination, two forms can seldom be connected by intermediate

varieties,

varieties

and thus proved to be the same species, until many specimens

are

have been

collected from many places; and →in the case of fossil species this

can

could

rarely be →effected by palæontologists. We shall, perhaps, best perceive the improbability of our being enabled to connect species by

numerous

numerous,

fine,

intermediate

intermediate,

fossil links, by asking →OMIT

our-selves

ourselves

whether, for instance, geologists at some future period will be able to

prove

prove,

that our different breeds of cattle, sheep, horses, and dogs

are

have

descended from a single stock or from several aboriginal stocks; or, again, whether certain sea-shells inhabiting the shores of North America, which are ranked by some conchologists as distinct species from their European representatives, and by other conchologists as →only varieties, are really

varieties,

varieties

or are, as it is called, specifically distinct. This could be effected →only by the future geologist discovering in a fossil state numerous intermediate

gra- dations;

gradations;

and such success →seems to me improbable in the highest degree.

Geological research, though it has added numerous species to existing and extinct genera, and has made the