Origin of Species Variorum

times, almost any amount of migration is possible. But in many other cases, in which we have reason to believ that the species of a genus have been produced within comparatively recent times, there is great difficulty on this head. It is also obvious that the individuals of the same species, though now inhabiting distant and isolated regions, must have proceeded from one spot, where their parents were first produced: for, as explained in the last chapter, it is incredible that individuals identically the same should .. have been produced ... from parents specifically distinct.

Single Centres of supposed Creation . —

We are thus brought to the question which has been largely discussed by naturalists, namely, whether species have been created at one or more points of the earths surface. Undoubtedly there are .. many cases of extreme difficulty in understanding how the same species could possibly have migrated from some one point to the several distant and isolated points, where now found. Nevertheless the simplicity of the view that each species was first produced within a single region captivates the mind. He who rejects it, rejects the vera causa of ordinary generation with subsequent migration, and calls in the agency of a miracle. It is universally admitted, that in most cases the area inhabited by a species is continuous; and that when a plant or animal inhabits two points so distant from each other, or with an interval of such a nature, that the space could not be easily passed over by migration, the fact is given as something remarkable and exceptional. The incapacity of migrating across a wide sea is more clear in the case of terrestrial mammals, than perhaps with any other organic beings; and accordingly, we find no inexplicable instances of the same mammals inhabiting distant points of the world. No geologist .. feels any difficulty in