STRATIGRAPHY OF CHI-LI AND SHAN-SI. 125 
ite is not visible. On account of the position of this section near the east 
end of the major synclinorium, it is not improbable that this is near the 
base of the Téu-ts’un formation. 
Vicinity of Tou-ts’un.—Seven miles, 11 kilometers, east of Téu-ts’un 
there is a ridge formed of an alternation of gray and buff limestones with 
dark argillites and occasional white quartzites lying in a syncline. ‘These 
strata resemble the Ta-yang formation of Chi-li more nearly than any 
other, but belong to the Hu-t’o system and probably chiefly to the Téu-ts’un 
group. On the southeast this syncline is overthrust upon Sinian limestone 
and is thus discontinued. 
Toward the northeast, where the ridge ends in a canyon which divides 
it from the slopes of Nan-t’ai, the Hu-t’o strata form the crest, but across 
the canyon we saw a thick and apparently continuous sequence of beds 
dipping steeply toward the north. They appear to be limestones or quartz- 
ites or both, interbedded with softer rocks, such as argillites or schists, and 
in dip and appearance correspond with the Wu-t’ai schists along the T’ai- 
SE NW 







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@glicatpereeraeer zx ( LS ee Kk: 
2S Lee 

Fic. 22 (Willis. Atlas sheet C I, section E E).—Section across contact of Hu-t’o (Pre-Cambrian) strata 
unconformable to Man-t’o shale, showing basal conglomerate. a = highly ferruginous conglomerate, 
pebbles of quartzite, chert and hematitic-limestone, in matrix of hematite; b = siliceous limestone 
and quartzite with some shale; c = red shale; d = Ki-chéu oolitic limestone, fossiliferous. 
shan-ho, 5 miles, 8 kilometers, distant in the direction of the strike. If this 
sequence is the southwestward extension of the Wu-t’ai rocks, the uncon- 
formity with the Hu-t’o strata, that form the upper portion of the peak 
from which our observation was made, should be found in the lower slopes. 
The moderate dips of the Hu-t’o contrast significantly with the steep 
isoclinal succession in the depths of the canyon, and an excellent oppor- 
tunity is here afforded to determine the relations of the two systems. 
The hills immediately south of Tou-ts’un show banded cherty lime- 
stones of gray, buff, and pinkish tints, with thinner layers of white quartz- 
ite. The softer gray slates appear in the passes and slopes, but are largely 
covered by the alluvium and loess of the valley. 
South by east of Té6u-ts’un the higher ridge adjacent to the Sinian 
outcrop is composed of hard gray flinty limestone, believed to be a part 
of the Tung-yti group. At the entrance to the canyon of the Shi-t’ou-ho 
