188 Editorial Comment. 
EDITORIAL COMMENT. 
A New Glacial Theory. 
The elaborate review of ''glaciers aud glacial radiants" by Dr. 
Claypole published in this number of the Geologist seems to 
point to the necessity of two conclusions that bear on the main 
question of the cause of the glacial epoch. 1st. The cause, what- 
ever it was, was terrestrial rather than eosmical. There does 
not appear to have been that general polar ice-cover which has 
been supposed. The northern part of Asia, under eosmical 
causes, must have been as well fitted for glaciers as northern 
America or Europe. 2nd. The cause which exempted Asia 
from perpetual land-ice and not America and Europe could not 
have consisted in any seasonal or annual increment of average 
cold for the northern hemisphere but must have been due to 
some change in the physical relations of the continents to the 
climatal agents that determine the existence or absence of per- 
petual ice. 
These reflections are prompted by a new "glacial theory" that 
has been proposed by Prof. Franklin R. Carpenter of the Da- 
kota School of Mines, with which the considerations pi-esented 
by Prof. Claypole are in perfect accord. 
In a recent letter to one of the editors he suggests that the 
great Tertiary, or Quaternary eruptions of molten lava which 
spread over large areas in North America and Europe, had a 
profound effect on the climate of those continents. Such effect 
must have been a local elevation of temperature. The effect of 
such local elevation of temperature would be the certain and 
long continued transference of the moisture that is borne by 
the western and south-western winds further toward northern 
latitudes. Once within colder latitudes aud beyond the effect 
of the lava sheets, this moisture would be precipitated in great 
volume in certain areas wherever it met with the condensing 
action of northern winds or higher altitudes. "The eruptions 
were accompanied probably by vast volumes of steam and clouds 
of volcanic ash. The effect of the first would be to augment 
the amount of precipitation, and the second, slowly settling to 
the north, would intercept the sun's rays and tend to increase 
the cold, as the ashes of Krakatoa seem to have done." 
