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but which do not offer the evidence required by the Darwinian 
hypothesis. The following are the chief considerations brought 
forward by Mr. Darwin, to break the force of this objection, 
though he admits his inability to assign a due proportional 
weight to each. 
a. It is maintained that each formation is probably “ short, 
compared with the period requisite to change one species into 
another.” Seeing that each formation is characterized by ail 
assemblage of living beings peculiar to itself, that few species 
pass through an entire formation, and that each subdivision of 
a formation is generally recognizable by its own peculiar forms 
of life, I do not see how it is possible to maintain this asser- 
tion. It may be noted, also, that though the amount of time, 
as having elapsed since the introduction of life upon this 
planet, demanded by the Darwinian theory is notoriously enor- 
mous, one has little idea of its immensity till one comes to 
analyze such an argument as that given above. It is admitted 
that the length of time indicated by our entire series of 
stratified rocks, is vast almost beyond conception ; but the 
entire series consists of only fourteen or fifteen great forma- 
tions, and would, therefore, irrespective of the blanks between 
the formations, correspond, on the above view, with less than the 
combined life of fifteen successive species. When we reflect 
on the enormous number of living forms that have died out, 
and the enormous number of new forms that have come into 
being, we feel hopeless of forming even an approximate con- 
ception of the time which Mr. Darwin asks for the carrying 
out of his theory. 
b. It is alleged, again, that the first appearance of a species 
in any formation, probably only indicates that it had then 
first immigrated into that area, and that it might have been in 
existence elsewhere for a long period of time. This may in 
some, perhaps in many, instances be true ; but there can be 
very few cases capable of definite proof, and it must, there- 
fore, be regarded as more or less of tbe nature of an assump- 
tion. It can hardly be asserted that in the long lapse of 
geological time we have not record of the first appearance of 
many species ; and we can never know, in most instances, 
whether the first appearance of a species, as known to us, is 
actually its first appearance, or is only so for the area under 
examination. Little weight, therefore, can be attached to this 
argument. 
c. In order to get a perfect gradation between two forms, 
we should require them to have lived in the same area for a 
long period, during which a thick and continuous scries of 
