STRUCTURAL GEOLOGY OF SHAN-TUNG. 71 
In its bearing upon the question of rate of displacement, this con- 
clusion indicates that the relief due to faulting developed more rapidly 
than channels were deepened by master streams at the time of faulting. 
It will appear in considering the course of the Huang-ho, and discussing 
the physiography of Central China, that the same is now true even of that 
great but overloaded river. 
Date of faulting.—The youngest rocks which are traversed by these 
normal faults, and whose age has been definitely ascertained through 
fossils, are of the upper Carboniferous. Succeeding them, and also cut 
by the faults, are volcanic rocks, which are tentatively assigned to the 
Permian by von Richthofen. We have no new evidence to offer as to 
the Permian or Triassic age of these eruptives, but agree that they are 
probably not younger than early or middle Mesozoic. We may, therefore, 
say that the normal faults are certainly Post-Carboniferous and in all 
probability Post-Triassic. This is as far as the evidence of stratigraphy 
enables us to go in determining their age; but physiographic facts afford 
narrower limits. 
As is more fully set forth in the discussion of the physiography, the 
relief of Shan-tung presents aspects of a more than mature character; thus 
while the faulted structure invites comparison with the Basin Ranges of 
the United States, the topographic aspects do not in the same degree, 
since in Shan-tung we find isolated mountain groups, whereas in the Great 
Basin we see continuous mountain ridges. In the Sin-t’ai district the 
isolation of mountain groups is due to the faulting itself, but in the 
T’ai-shan, the Shi-m6én-shan, and Kiu-nii-shan the isolated mountains 
constitute a chain, having the linear though interrupted character of a 
dissected ridge. Such these mountains are. They were formerly con- 
tinuous ridges, but they have been cut through by consequent streams 
developed on their scarps and back slopes. A similar process of dissec- 
tion is begun in the Basin Ranges, but it is very far from being equally 
advanced. Discussing the forms of the Basin Ranges, Davis says:* 
“The body of each range is usually continuous, although it may be incised by sharp 
cut valleys; if the ranges were the residuals of a period of undisturbed erosion long enough 
to have permitted the excavation of broad intermont valley-lowlands, each range should be 
divided into isolated mountain groups by the opening of wide branch valleys in its mass.” 
It is thus evident that the fault-blocks of Shan-tung are further 
advanced in their erosion cycle than are the similar masses of the Basin 
Ranges. This conclusion would follow with equal clearness if we compared 
the skeletonized heights of Shan-tung with the full-bodied mountains of 
the Great Basin. 
* Davis. Science, N. S., vol. XIV, p. 459. 

