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directions , and thus of giving rise to a definite series of specific 
types. 
12. It further remains for future consideration, whether this 
orderly process of evolution has always been effected in a 
gradual manner, and whether it has not been occasionally 
effected by changes taking place suddenly and per saltum. 
13. Finally, it remains to consider within what limits evolu- 
tion has operated, and what supplementary causes may be 
found to have acted in the production of new forms of life. 
Or, rather, it remains to consider whether evolution is a 
main, or only a subsidiary agency in the production of new 
species. 
The Chairman. — I am sure the meeting will pass a cordial vote of thanks 
to Dr. Nicholson for his paper. It is now open for any of those present to 
make observations thereon. 
Rev. G. Henslow. — I think we must all feel greatly indebted to Dr. 
Nicholson for this paper : in it he has distinctly pointed out a matter upon 
which I have reason to think that there is some confusion in the public 
mind. I mean the distinction between Darwinism and Evolution; the 
former, involving as it does the theory of natural selection, I do not hold ; 
but there is a great difference between natural selection and evolution. 
Again and again have I stood up on behalf of evolution, but I have always 
felt that natural selection, pure and simple, would never be sufficient to 
account for it. I do not know, however, that I agree entirely with all 
Professor Nicholson’s views. For instance, with reference to the poverty of 
our Palaeontological collections ; in my opinion, a strong point should be made 
in regard to the evidence that is wanting. Mr. Darwin speaks of the 
paucity of the geological record ; but there is one thing that ought not to be 
forgotten : — When we examine certain strata and calculate their thickness, 
we get something obvious before us, but we are apt to forget, at the same 
time, that every one of those strata is just as much a measure of what is lost, 
as it is of what we have before us. When we consider the Laureutian strata, 
the question' arises, where did they come from '? If they are so many 
thousands of feet thick, there must have been so many other feet of thick- 
ness of primitive strata, about which we know nothing at all, and those 
primitive strata might have been full of life. For instance, take the sand 
upon the sea-shores of the south-east of England, where the chalk strata are 
to be found : the sand, of course, is formed from the wear and tear of the 
chalk-flints, which are derived from the denuded cliff ; but if you take the 
sand of the sea-shore of Scarborough, this is not the first time it really has 
been sand : the sandy beach results from the denudation of the fresh-water 
strata which form the rocks round the coast ; so that the same sand must 
have been used at least twice, if not many times over. Every stratum is 
