T H E 
AMERICAN GEOLOGIST 
Vol. III. FEBRUARY, 1889. No. 2. 
GLACIERS AND GLACIAL RADIANTS IN THE ICE-AGE. 
Bv Dr. E. W. Claypoi.e, Akiion, O. 
The Glacial Theory has already in its comparatively brief ex- 
istence seen several ebbs and flows. The great principle of 
glaciation laid down by Agassiz aud Guyot has never been suc- 
cessfully assailed. That at least one era has occurred in the 
history of the earth when ice played a very conspicuous part is 
now doubted by few, though the exact extent of its action is 
among the unsolved problems in geology. It has been so with 
other geological questions that have from time to time passed 
under discussion. Long after the main principle involved has 
been accepted by all parties there remain numerous points of 
detail requiring for their final settlement tedious and careful 
investigation. 
It is this, we may remark in passing, that often leads men 
not familiar with the subject to charge geology with uncertainty, 
to denounce it as a mass of speculation destitute of all solid 
base and to declare that what one age builds up the next pulls 
down. This is utterly untrue regarding the main doctrines of 
the science and to make the assertion indicates a want of exact 
knowledge of the subject. 
Among other doctrines of geology that come in for their 
share of popular scepticism in this way is the glacial theory. 
Now the doctrine that ice has had much to do in comparatively 
recent times in moulding the contour of the surface in the 
higher latitudes of the earth is well established, but its influence 
has been alternately magnified and diminished as the pendulum 
has swung now this Avay and now that. 
The author of this theory — the late Prof. Agassiz —in his per- 
haps pardonable enthusiasm over his new-found geological 
engine, went so far as to ai«sert that evidences of glacial action 
