80 
OROGENY AND EARTH’S ROTATION 
During all this time, and longer, as George Darwin well observes, 
the Polar regions must have been ever rising and the equatorial 
belt falling, though as the ocean followed these changes they 
might quite well have left no geological traces. 
In this connection the telluric tides of this early day of rapid 
rotation is not without great significance. The older Paleozoic 
and Pre-Cambrian rocks have not as yet been subject to critical 
examination with possible effects of this kind directly in view. 
The Cambric and Pre-Cambrian section of the Rocky Cordillera 
in Alberta and British Columbia seem to be most promising fields 
of inquiry. The Great Basin recently comes into this category. 
The Canadian Shield needs special consideration in this respect. 
The ancient crystallines of the Piedmont Plateau in Maryland and 
Pennsylvania already yield important results bearing directly upon 
this theme; as do also the Pre-Cambrian fields of the Scottish 
Highlands. When these regions have been carefully inquired into 
the failure or realization of Elie de Beaumont’s reseau pentagonal 
will have been satisfactorily explained. 
In the laboratory experimentation on curved prisms, like sec¬ 
tors of the earth, with bands to take the place of gravitational 
control, and under conditions analogous to retardation of the 
earth’s revolution, there is reproduced to a nicety all of those 
larger structural features of the earth such as the ocean basins, 
the continental arches, the cordilleran corrugations, and the orogra- 
graphic foldings. The effects of tangential creeping which many 
mountain structures display thus appear to be not due necessarily 
to results of the earth’s contraction, but to direct cumulative 
lelease due to secular retardation of the earth’s rotation. 
On this new basis, with the force and rate of retardation, and 
the amount of crustal shortening capable of exact expression by 
mathematical equation a ready means is provided for realizing not 
only something of Elie de Beaumont’s fantastic dream of orogra¬ 
phic symmetry, but for guaging in units of human time the age of 
every mountain uplift, for determining within very narrow limits 
in like terms the periodicity of every diastrophic movement, and 
for evaluating in years not only the span of every era, period, 
epoch and stage of the stratigraphic record since life began on our 
globe, but for guaging stratigraphic chronology long antedating 
the life record. 
