472 RESEARCH IN CHINA. 
From this description it is obvious that the specimen has its nearest 
allies in the black oolite of the Ch’ang-hia limestone,* closely resembling 
that rock in texture and structure. It preserves, however, even fewer of 
the familiar characteristics of oolites, and must be considered as represent- 
ing a slightly more advanced stage in the crystallization of the rock. 
MESOZOIC, 
The upper coal-bearing series, or red beds, of Ssi-ch’tian have been 
shown, by Pumpelly and Richthofen, to belong to the earlier Mesozoic. 
The contact with the underlying Paleozoic limestones has not yet been 
observed in this district, but it is undoubtedly unconformable. ‘This series, 
to which we apply the name K’ui-chéu formation, is composed of weak 
sandy and shaly strata which are interbedded with occasional banks of 
limestone. ‘The character of the rocks differs considerably in the different 
areas observed. Many of the rocks are reddish. As yet no igneous intru- 
sives have been found in association with the formation in any locality. 
RoOcKS OF SEDIMENTARY ORIGIN. 
PSEPHITES. 
Black flint conglomerate, No. 147.—The exact place which this con- 
glomerate occupies in the vertical scale is unknown. Our specimen was 
found in the float along the Ta-ning-ho, 7 miles, 11 kilometers, below Ta- 
ning-hién. The abundance of pebbles of black flint in the rock indicates 
that it was developed during the erosion of the flinty Wu-shan limestones. 
On this account there can be little doubt that it is Post-Carboniferous in 
age. The balance of evidence indicates that it is probably a basal con- 
glomerate in the K’ui-chdéu series. 
The conglomerate is composed of rounded and subangular pebbles 
which have evidently been waterworn. The pebbles average less than 1 
inch in diameter, although the maximum size is more than 2 inches. They 
are composed almost entirely of black and banded cherts with a few gray 
flints and bits of white vein-quartz. The matrix in which these pebbles 
are embedded is a firm impure sandstone of light-brown color. 
The pieces of black flint are exceedingly fine-grained and appear brown 
rather than black in the slide. The flints are undoubtedly composed very 
largely of quartz, but this is so mingled with dark impurities that it is 
hardly possible to differentiate any of the components of the rock. In the 
pebbles of white quartz strain-shadows are very prominent, and on this 
account it is inferred that they have been derived from the Pre-Cambrian 
rocks, since strain effects are rarely prominent in the younger series. 

* See page 381. 
