104 
ISOSTATIC THEORY 
veins associated with profound faults have some genetic con¬ 
nection with telluric tectonics appears to be a necessary con¬ 
sequence of their orderly geologic setting. That such ore-veins 
are the direct, albeit somewhat different, expressions of the same 
compressive stresses which initiate mountain ranges and form the 
major plaits of the earth’s crust seems to present small doubt. 
The surmise is not a wholly unexpected impression derived 
from casual observation and fitful acquaintance with western 
American ore deposits. Even the remarkable uniformity of hade 
and the surprising sameness of trend demand for their explanation 
something more than mere fortuitous occurrence. What the basic 
law shall prove to be may not be so far away as might be imagined. 
When once formulated this law must constitute for modern ore 
exploration its most advantageous adjunct. 
Notwithstanding the fact that steep dip is the most striking 
feature connected with Western fissure-veins, for example, the 
extreme uniformity usually claimed does not appear to be nearly 
so prevalent as might be inferred from perusal of the literature 
on the subject. There are many and noteworthy deviations. 
Despite the numerous apparent exceptions to rule and a multitude 
of erratic examples which have yet to be brought into accord, the 
frequency of small hade is doubtless to be regarded as a direct 
function of telluric relationship. Then, too, the variable steepness 
of inclination may prove eventually to be an index to geologic 
age — the smaller the hade the younger the fissure; and con¬ 
versely, the lower the dip the greater the antiquity of the slipping. 
For this aspect there seems to be fundamental cause. 
The larger or telluric relationships of ore-bodies never receive 
the genetic attention which they really merit, probably mainly for 
reason of their universally supposed local character. In this re¬ 
gard there are, indeed, few geological phenomena which are so 
well adapted to supply critical data as dislocative fissure-veins. 
Recent laboratory experiments have a direct and curious bear¬ 
ing upon this very problem. All of the grander relief and 
structural features of our planet are so perfectly reproduced that 
the replicas in miniature seem to indicate thatl in nature they are 
the immediate effects of a diminishing rate of the earth’s rotation 
upon a heterogeneous crust or zone of rock-fracture. In the fifty 
odd millions of years which have elapsed since Mid-Paleozoic 
times, when the sidereal day was only about one-fourth so long as 
