[336]

On reflection I certainly think that vars. must be produced in many spots of widely extended areas of varying species (thus parent-form remaining same perhaps in some) - chiefly found in isolated spots - hence will not soon commingle for & indeed if spot be not isolated, will not spread till becomes considerably different & so on to having some decided advantage. Of these vars or quasi-species, the most distinct will be preserved, & on any one spot will come in like new creations & exterminate some old forms. On a small spot like P. Santo, a land-shell will form a variety slowly & [illeg], all parent-form being changed, but this may take a very short, compared with whole existence of the variety - Hence chance if intermediate fossil Q? being formed small.

[in margin:] These remarks apply to more important variations like species & not more casual [abnormalities]