288 RESEARCH IN CHINA. 
SECTION ACROSS THE KIU-LUNG-SHAN. 
Synclinorium: Wu-shan-hién to Kiu-shi-li-p’u.—Between Wu-shan- 
hién and Kiu-shi-li-p’u (Ta-ch’ang), a distance of 12.5 miles, 20 kilo- 
meters, Fig. 62a, the Ta-ning-ho flows across the strike and crosses 
four anticlines in the Wu-shan (Carboniferous) limestone, and the five 
adjacent and included synclines, which are occupied by the K’ui-chéu 
(Permo-Mesozoic) red beds (section, atlas sheet d 7). The whole structure 
is in effect a synclinorium, it being bounded both north and south by 
higher anticlines; and it is a very flat one, since the difference in altitude 
for a given stratum such as the top of the Wu-shan limestone, does not 
exceed 4,500 feet, 1,500 meters. The base of the Wu-shan is not exposed 
on the highest anticline in this subsection, and the thickness of the K’ui- 
chéu beds contained in the deepest syncline is. probably less than 2,000 
feet, 600 meters. A total of 5,500 feet, 1,650 meters, of strata is prob- 
ably a maximum of what we saw between Wu-shan and Kiu-shi-li-p’u. 
The folds are not only shallow, but also broad, and the curvature is even, 
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Fic. 62 (Willis).—Geologic section across the Kiu-lung-shan and on the Ta-ning-ho, from Chén-p’ing- 
hién, Shen-si to Wu-shan-hién, Ssi-ch’uan—reduced from sections in the atlas (continued in Fig. 62a). 
without sharp accents, except that the central syncline appears to have a 
keel of the K’ui-chéu red beds pinched in the top of the limestone. The 
great arches of limestone, trenched by the river in exceedingly narrow 
canyons with vertical walls, exhibit with rare beauty and clearness the 
vertical and horizontal distribution of stress and yielding in a massive 
uniform bed which has undergone moderate flexure. 
The pitch of folds, 7. e., the inclination of axes, where we crossed 
them, is sometimes to the west, sometimes to the east. By inspection of 
the geologic map (Wu-shan-hién sheet d 7) it will be seen that the Wu- 
shan-hién syncline extends both east by north and west by south beyond 
our observation. If we may trust maps based on Chinese sources for 
the courses of streams and roads that would follow the synclinal valley, 
the length of the latter is probably not more than 50 miles, 80 kilometers, 
and possibly much less. The two little synclines next north in the 
Ta-ning-ho section appear to be near the western end of the syncline of 
K’ui-chéu, Hu-pei, in which the Yang-tzi takes its course below the Wu- 
