194 
that the author has rested too much on mere negative evidence in the 
conclusions he has drawn with regard to one of the most remarkable 
problems of natural science which has ever been brought before the in- 
tellectual world. Negative evidence, I admit, may be carried to a point in 
which it may be said to have almost the same weight as positive evidence ; 
but, I would ask, is this the case with the negative evidence upon which the 
opponents of the doctrine of evolution rest ? I answer, most assuredly 
not. It is impracticable at this late hour of the evening to attempt 
to go through all the various points and interesting string of facts and 
reasoning we find in Mr. Callard’s paper. I will, therefore, simply call 
attention to one matter, which I think he relies upon as his sheet 
anchor in his opposition to the doctrine of evolution. It is this : that, in 
order to establish that doctrine, it must be proved that there has been a con- 
tinuous series of life forms, carried onwards by numberless insensible grada- 
tions, from a low to a high type, through all the various phases of animal life 
which we find represented on or in the crust of the earth ; and that this 
series of multitudinous forms shall have had no break. Now coming to 
what the author has said, with regard to the alleged break in the Cretaceous 
period, I would ask your attention to this passage : — “ I come to the 
Cretaceous, and no part of such series can be shown. So far as the present 
evidence goes, there is a break in the continuity of mammalian life in the 
Cretaceous period.” Here, in referring to mammalian life, I must ask you 
to bear in mind that the doctrine of evolution does not restrict itself to 
mammalian life. It includes the whole range of animal life ; but to-night 
we are dealing with mammalian life. Now the Cretaceous system of rocks 
forms a very large portion of the whole series of fossil-bearing strata. It 
extends from England over thousands of square miles in Europe, and 
again we have it in North America ; and it is true that in all parts of the 
world, wherever this system of rocks has been explored, we have found 
no trace of land mammalian life. Consequently ]\Ir. Callard has come to 
the conclusion, and I am not surprised at it, that there was no mammalian 
life in that period. But this conclusion, I say, is wholly and entirely 
illogical, and can be at once refuted and extinguished by any one who has 
had anything like a large practical experience in the exploration of 
fossiliferous strata. I will give you chapter and verse, by citing a 
perfectly parallel case, to prove how utterly worthless — I am sure Mr. 
Callard will forgive me for using so strong a term — is the conclusion he 
bases on this apparent break in the continuity of past mammalian life. There 
is, in East Anglia, a geological formation which is locally known under the 
name “crag” ; with regard to which I may say, that when William Smith 
founded the science of Geology, some fifty or sixty or years ago, he, and 
other geologists, adopted the local name “ crag ” as a geological term. Of 
course, when Geology began to rank as a science, geologists had to construct 
a terminology denoting the different strata. When they could find a 
name that was in common use, they took it. “ Chalk” is a case in point, 
for that name has become incorporated in all systems of stratigraphica 
