STRUCTURAL GEOLOGY OF SHAN-TUNG. 63 
STRUCTURE OF THE SINIAN IN THE CH’ANG-HIA DISTRICT. 
Detailed observations.—In the Ch’ang-hia district strata of the Sinian 
system dip gently toward the northwest, so that, within the area surveyed 
in detail, in a distance of 16 miles, the entire sequence passes underneath 
the plain. This fact was correctly described by von Richthofen,* who 
reviewed the strata rapidly, in journeying along the highway, which here 
leads in a northwesterly direction. It happens that the valley, and conse- 
quently the highway, lies near the axis of a broad anticline, the pitch of 
which is represented by this northwesterly inclination. The dips on the 
flanks of this anticline are not noticeable in a general view, and escaped 
the attention of von Richthofen. 
The following are some of the more notable local structures: Section 
AA, Plate XV, shows the attitude of the strata in the ridge east of Ch’ang-hia, 
from the base of the Man-t’o northwestward and northward to the point 
where the Ts’i-nan limestone disappears under the plain. The gentle 
undulatory northwest pitch of the massive Ch’ang-hia oolite, the Ch’au- 
mi-tién limestone, and a small part of the Tsi-nan is clearly brought out. 
On the line of this section a local feature of deformation in the Man-t’o 
shale and the lowest layers of the Ch’ang-hia oolite is well exposed in a 
valley northeast of Ch’ang-hia. In the thin-bedded Man-t’o shales there 
occurs a sharp anticline which is overturned toward the south. The 
strike of the axis is about N. 75° E. The nearly vertical and overturned 
dips occur also in the lower of the limestone layers, but are not represented 
in the upper portion of the Ch’ang-hia oolite, which is practically flat. 
A section on a line at right angles to the preceding is shown in BB. 
It passes through the isolated hill, Man-t’o Butte, and exhibits a difference 
of elevation between the base of the Man-t’o formation on the east and 
west of the valley, of 700 feet, 210 meters. Von Richthofen observed this 
difference and commented upon it.t Believing the strata to be horizontal, 
he inferred the existence here of a normal fault, of a type which is common 
elsewhere in the province. The base of the formation dips in Man-t’o 
Butte, as shown in the section, and its continuation westward may readily 
have risen higher than we now observe, to connect ina fold with the outcrop 
in the next ridge. The axis of the fold has been eroded. We did not 
observe any evidence of faulting. 
In the northwestern part of the area mapped, in the valley south of 
Ch’au-mi-tién, the limestone of that name shows dips of 60° to 80°, while 
striking nearly north and south. The probable structure is delineated in 
Section CC, Plate XV, as a sharp syncline. Occurring in the base of the 
Ch’au-mi-tién limestone, and thus involving a part of the rigid uppermost 

* China, vol. u, pp. 195-197. Tj Ibid., p. 196. 
