GEOLOGICAL CLIMATES 
305 
This would re-inaugurate geologic climates and the ultimate 
chilling of land-masses, with still warm oceans, and resultant 
dense clouds would give a corresponding series of climatic events 
to that recorded within the reach of the geologist. 
It is not improbable that such phenomena may have character¬ 
ized pre-geologic eras; and that the eras of geologic history are 
only the last chapters of the formation of the fully tested and 
stable crust. 
Under neither of the above possibilities may future glaciation be 
regarded as an impending event. 
The conclusions applied apparently have analogies offered by 
other planets. Such application can now be made only under a, 
broad interpretation of the features presented by the planets 
which are selected for this purpose. 
If the principles herein used for the interpretation of the 
climates of the earth have been rightly selected and applied, and 
the conclusion correctly reached and found to fit the geologic 
record and present conditions, these conclusions have certain 
general applications to the other members of our solar system. 
This is well brought out by Iteschel, Chamberlin and Salisbury, 
Barnard and Campbell. 
During the greater part of geologic time, it is held that the 
earth was swathed in clouds ranged in zones parallel with the 
equator. This cloud-sphere was practically continuous, and pre¬ 
sented a surface of high albedo — that of clouds, or about .60. 
At present this surface is broken, and the albedo has been lowered 
by the exposure of about 48 per cent of its dark surface. More¬ 
over, it is known that the violet end of the spectrum is utilized 
to a greater extent than the red end, and hence this end controls 
the color of the reflected ray.^ 
It follows that a planet in this, or in a later, stage of climatic 
development has a low albedo, and the color of its reflected light 
is that of the least utilized end of the spectrum. The earliest 
of these stages must be presented by the larger planets, whose 
masses have imposed a longer period of cooling, and they present 
a cloud-banded surface of high albedo. 
The latest stage must have been reached by the smaller planets 
2 Hence the copper red of the “earth shine" on the new moon, which reflects greatly 
reduced but normal light from the crescent. 
