508 
glaciers that swept over the region. The materials of the Seven-Mile Hill 
depesits and those beneath the lava flows of the Nantan plateau indicate 
that the glaciers came from the White Mountains to the eastward. This is 
also indicated by the dip of the clays and sands. But the deposits of the 
Cibicu divide indicate by their composition that they came from. the west 
and northwest (and possibly from the southwest), as do also the Hinton 
and Salt river deposits the latter being composed of quartzites, gneiss, vitre- 
ous Tonto sandstone, Archean and Palaeozoic rocks, and biotite granite, all 
of which are exposed in the upper Canyon creek region, the Ellison dome 
and the Tonto basin, and south of Salt river along the western face of 
the Plateau. It is also quite probable that some of the debris came from 
the mountains to the northward. 
From the inadequate data at hand it would seem that at least the deposits 
below the partly consolidated conglomerate series are Tertiary, extending 
to the early Tertiary. as Gilbert, Marvin, and the writer coneluded when 
examining the region, and that the remainder are Quaternary, as was also 
then concluded. This being the case, as the facts at hand seem to indicate, 
we would, therefore, have had glaciation here in the early Tertiary, prob- 
ably in the Eocene period, repeated again in the Quaternary. Laking in 
consequence of blocking lava flows and faulting probably played their 
parts as did also the subsequent development of drainage, which is, in 
part, inverted and, in part, diverted. 
The finding of glacial material forming the opening series of the Eocene 
in many parts of the world brings again to the fore with emphasis the fact 
that glacial epochs have occurred at the beginning (or the close) of each 
great era of geologic time. This raises the question again, Why do geologic 
eras close? Is there not a cosmic cause? And as the writer has sug- 
gested in previous publications.* may not these changes both in climate and 
in the readjusting and rebuilding of the earth’s crust be due fo results 
brought about by our solar system having reached one or the other terminus 
of the great elipse around which it is whirling with its company of planets, 
meteors, planetoids, secondary planets, and comets, much as our extreme 
yearly seasons are caused by similar positions of the earth with reference 
to the path it travels around the sun and to the inclination of its axis. 
*Regan, Albert B., The Glacial Epoch, Trans. Acad. Sci. of Kansas, Vol. XXVI, 
1913, pp. 70-83; Sunspot, Vol. 1, No. 11, January, 1916, pp. 13-30. 
