210 
fixed and unalterable lines, but solely according to chance 
variations in its environment and surroundings, or in its 
internal structure. On the other hand, there are other minds 
to which “evolution,” in so far as we may believe it to have 
occurred at all, presents itself as a perfectly orderly and 
definitely regulated process, as much a part and parcel of the 
Divine order, and as thoroughly conformable to it, as any other 
conceivable mode of creation. On this view, certain types of 
life have been so endowed as to give rise to certain other 
related types by “ evolution,” — the evolution not taking place, 
or capable of taking place, in any or every direction, but 
following a certain definite and necessary line. This is the 
“ genetheonomy ” of Mr. Davidson and Professor King, the 
“ evolution of species effected mainly through the operation of 
Divine laws, and not by purposeless or accidental modifications.” 
For my own part, if we substitute, in the above quotation, the 
word “wholly” for “ mainly,” I see no difficulty in accepting 
evolution as an agent in the production of species. It will be 
observed that this leaves open the question as to how far 
evolution has thus operated, and also as to how its operation 
has been effected, whether by “natural selection,” or in some 
entirely different manner. 
Having now cleared the ground by these preliminary con- 
siderations, I shall pass on to discuss the method in which Mr. 
Darwin has treated the difficulties which palaeontology offers 
to the acceptance of his theory of the evolution of species by 
natural selection, as expounded in the chapter of the “ Origin 
of Species,” entitled “The Imperfection of the Geological 
llecord.” And I may here remark, that though I have come 
to the conclusion that Mr. Darwin has failed to remove these 
difficulties entirely, or even to materially lessen their weight, 
lie has exhibited conspicuous fairness in the manner in which 
he has stated them, and that his arguments embrace much of 
the highest value, quite apart from the special conclusions 
which may be drawn from them. The subject may be con- 
sidered under the following heads. 
1 . The Nat ure of Extinct Intermediate Varieties. — Mr. Darwin 
commences by pointing out that at the present day, sup- 
posing his theory to be true, we should not expect to find 
any forms directly intermediate between two given species, or 
that, at any rate, the existence of such forms must be very 
rare and exceptional. What we should look for are “ forms 
intermediate between each species and a common but unknown 
progenitor.” It is clear, however, that as regards extinct 
species, we have a right to look for such directly intermediate 
