134 RESEARCH IN CHINA. 
after a space of a mile or more, they are involved in moderate folds and are 
finally cut off on the north by the overthrust mentioned above. ‘To the 
west of the village the Ta-yang formation is broadly exposed in low hills 
which are partially soil-covered. This area continues southwestward 
north of the city of Kti-yang-hién, for an undetermined distance. The base 
of the section near Ta-yang was not actually observed owing to the fact 
that the contact is largely obscured by the soil of the surrounding low- 
land, but not more than 20 feet, 6 meters, above the gneiss the strata 
are gray flinty limestones of fine texture and somewhat 
argillaceous composition. Freshly broken surfaces 
appear clean and uniformly gray in color, but the 
weathered exteriors are ash-gray and are covered with 
an earthy residuum. ‘These gray limestones, in which 
nodules and lamine of flint are abundant, continue 
upward through a thickness which, though not deter- 
mined, is estimated at several thous- 
and feet. At certain horizons the 
strata are dark in color and less 
purely calcareous. About 800 feet, 
240 meters, above the base, a thirty- 
foot layer of white quartzitic sand- 
stone appears in this locality. Aside 
from these slight variations, the 
sequence is notably uniform. The 
flint nodules which are so character- 




Fic. 30 (Blackwelder).—Wang-k’uai-chén, Chi-li. 
Unconformity beneath Ta-yang (Algonkian) 
istic of the formation are usually limestone, showing basal shales lying upon 
black, but it is not rare to find cherts weathered and eroded gneiss (Archean). 
f hit buff color a = caleareous brown shales, micaceous at 
gi See os adeno > the base; 6 = impure sandstone; c = gray 
In the hills east of Wang-k’uai- calcareous shale; d = gray limestone; e = 
chon, the basal complex lies against gray flinty limestone with thin layers of gray 
He : and buff shale. 
the Sinian limestone along a normal 
fault. Upon this upthrown block of the complex there is an outlier of 
the Ta-yang limestone, representing several hundred feet of the forma- 
tion (see Fig. 30). In this case the basal portion consists of shales, quickly 
followed by a sequence of gray flinty limestones. 
A similar outlier, exhibiting only 200 or 300 feet of the sequence, is 
situated about a mile,1.5 kilometers, east of Féu-p’ing-hién, in the summit 
of the mountain, upon which a temple is built. Here also the limestones 
lie unconformably upon the basal complex, with a thin member of red- 
brown shales intervening. 
