[81]

In large continent, the individuals of each species from being exposed to various conditions & from crossing the sub-sub varieties, cannot be so perfectly adapted to conditions, as in island - This must hold good to whole fauna & therefore a species from neighboring islands from being more closely (conformable to their conditions, will exceed & beat out the continental species.

(22)

In old times there have been genera, families &c &c. If every species had heirs, the number would be infinitely great in times to come - but if we suppose the number of individuals & divisions equal in these times, only a few individuals can have descendants, hence much extinction in proportion to metamorphosis: hence gradation not or only seldom discoverable in thick stratum.

N.B. The adaptation of any species to conditions, must chiefly depend on adaptation of other species in same country, so that the perfection of adaptation in two countries may possibly vary: under a changing climate, species less conformable, then in old fixed climates.

[81v]

Is it not said, that those shells now living which also lived in old geological periods are shells with wide range; & thus are supposed to have escaped extermination: is it not rather, that those shells with wide ranges, if not exterminated, will probably remain with same specific character & hence called same species.