Origin of Species Variorum

have attempted to show that the geological record is extremely imperfect; that only a small portion of the globe has been geologically explored with care; that 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, perhaps, 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, and have oftenest given rise to new species; and that varieties have at first often been local. .. These causes taken conjointly, must have made the geological record extremely imperfect, and will to a large extent explain why— though we do find many links between the members of the same group— we do not find interminable varieties, connecting together all .. extinct and existing forms .. by the finest graduated steps. ↑

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