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Cocxsurn-Hoop.— New Zealand a Post-glacial Centre of Creation. 18 
elaboration of new species, by the “ aimless action of Natural Selection," 
necessitates the granting of thirty times the number of millions of years 
physical considerations render it possible to allow, as Dr. Tait states the 
question, the difficulty of the position will not be lessened by Herr Haéckel’s 
bold assertion, that ** we have not a single rational ground for conceiving 
the time requisite to be limited in any way." 
This writer, although he deems very slow progress to have been the 
rule, leaves his readers to believe in the possibility of exceptions to it. 
Notwithstanding the small advances made during the recent period in any 
line of life (how the cats, the dogs, and the pigeons of the days of the 
earliest Pharoahs remain represented but by pure cats and dogs and 
pigeons still, not one attempt at passing beyond the limit of its class 
having been made by any of these creatures, whose development has 
received such attention and studied assistance from man), they are not to be 
daunted by the proposition that in new centres of creation, such as New 
Zealand, the derivative process was by some means marvellously hastened 
in its accomplishment. 
Recurring periods of heat and cold extending simultaneously over the 
greater part of the world, may be convenient agents to call into requisition 
for the purpose of explaining the disappearance of many forms of organic 
life. The vanishing of others for a time, and their return to the same 
localities, displacing very different ones that in the interim had flourished 
there, is, no doubt, due to such cause. But had these cycles been repeated 
more frequently than even according to the views of Mr. Croll they have 
been—views much more within our grasp than the consideration of pro- 
cesses requiring cons paralyzing to the minds of most men who attempt to 
dwell upon them—they would not account for many of the events which we 
know have taken place in the history of animal life. 
Ten thousand or twenty thousand years may be deemed by evolutionists 
generally, periods altogether too short for the accomplishment of any of the 
processes of divergence and development necessary to the establishment of 
species, for which millions have been asked; but much could be done 
during such a vast lapse of years in the way of perfecting various families 
and the extinction of others. The recurring periods of the reign of frost 
over particular areas in alternate hemispheres, which have evidently taken 
place, would cause no violent changes, advancing as they must have done 
with slow enough steps to afford ample opportunity for the migration of 
existing forms of life to suitable situations, so long as any such remained 
for them to migrate to, which during this Glacial Epoch of Professor 
Haéckel were certainly reduced to a minimum. 
There was no ice-sheet enveloping their ancient haunts, which destroyed 
