Origin of Species Variorum

Comparison with 1861

such to have been formerly deposited; for it might well happen that strata which had subsided some miles nearer to the centre of the earth, and which had been pressed on by an enormous weight of superincumbent water, might have undergone far more metamorphic action than strata which have always remained nearer to the surface. The immense areas in some parts of the world, for instance in South America, of bare metamorphic rocks, which must have been heated under great pressure, have always seemed to me to require some special explanation; and we may perhaps believe that we see in these large areas, the many formations long anterior to the silurian epoch in a completely metamorphosed condition.

The several difficulties here discussed, namely— that though we find in our geological formations many links between the many species which now exist or have existed; the sudden manner in which whole groups of species appear in our European formations; the almost entire absence, as at present known, of fossiliferous formations beneath the Silurian strata,— are all undoubtedly of the gravest nature. We see this in the plainest manner by the fact that all the most eminent palæontologists, namely Cuvier, Owen, Agassiz, Barrande, Falconer, E. Forbes , &c, and all our greatest geologists, as Lyell, Murchison, Sedgwick, &C have unanimously, often vehemently, maintained the immutability of species. But I have reason to believe that one great authority, Sir Charles Lyell, from further reflection entertains grave doubts on this subject. I feel how rash it is to differ from these

such to have been formerly deposited; for it might well happen that strata which had subsided some miles nearer to the centre of the earth, and which had been pressed on by an enormous weight of superincumbent water, might have undergone far more metamorphic action than strata which have always remained nearer to the surface. The immense areas in some parts of the world, for instance in South America, of naked metamorphic rocks, which must have been heated under great pressure, have always seemed to me to require some special explanation; and we may perhaps believe that we see in these large areas, the many formations long anterior to the Silurian epoch in a completely metamorphosed but likewise denuded condition.

The several difficulties here discussed, namely— that, though we find in our geological formations many links between the .. species which now exist and have existed, we do not find infinitely numerous fine transitional forms closely joining them all together;— the sudden manner in which several whole groups of species first appeared in our European formations;— the almost entire absence, as at present known, of .. formations rich in fossils beneath the Silurian strata,— are all undoubtedly of the most serious nature. We see this in the ... fact that .. the most eminent palæontologists, namely Cuvier, .. Agassiz, Barrande, Pictet, Falconer, E. Forbes , &c., and all our greatest geologists, as Lyell, Murchison, Sedgwick, &c., have unanimously, often vehemently, maintained the immutability of species. But it is evident from the recent works of Sir Charles Lyell that he now almost gives up this view; and some other great geologists and palæontologists are much shaken in their confidence. I feel how rash it is to differ from the foregoing