Origin of Species Variorum

Comparison with 1866

only certain classes of organic beings have been largely preserved in a fossil state; that the number both of specimens and of species, preserved in our museums, is absolutely as nothing compared with the incalculable number of generations which must have passed away even during a single formation; that, owing to subsidence being almost necessary for the accumulation of .. deposits rich in fossils and thick enough to resist future degradation, enormous intervals of time have elapsed between most of our successive formations; that there has probably been more extinction during the periods of subsidence, and more variation during the periods of elevation, and during the latter the record will have been least perfectly kept; that each single formation has not been continuously deposited; that the duration of each formation is, probably, short compared with the average duration of specific forms; that migration has played an important part in the first appearance of new forms in any one area and formation; that widely ranging species are those which have varied most frequently, and have oftenest given rise to new species; .. that varieties have at first .. been local; and lastly, although each species must have passed through numerous transitional stages, it is probable that the periods, during which each underwent modification, though many and long as measured by years, have been short in comparison with the periods during which each remained in an unchanged condition. .. These causes, taken conjointly, ... will to a large extent explain why— though we do find many links between the species of the same group— we do not find interminable varieties, connecting together all .. extinct and existing forms .. by the finest graduated steps. It should also be constantly borne in mind that any linking varieties between two or more forms, which might be found, would be ranked, unless the whole chain could be perfectly restored, as so many new and distinct species; for it is not pretended that we have any sure criterion by which species and varieties can be discriminated.

He who rejects these views on the imperfection of the geological record, will rightly reject my whole theory. For he may ask in vain where are the numberless transitional links which must formerly have connected the closely allied or representative species, found in the successive stages of the same great formation? He may disbelieve in the enormous intervals of time which have elapsed between our consecutive formations; he

He who rejects these views on the nature of the geological record, will rightly reject my whole theory. For he may ask in vain where are the numberless transitional links which must formerly have connected the closely allied or representative species, found in the several stages of the same great formation. He may disbelieve in the enormous intervals of time which have elapsed between our consecutive formations; he