RECONNAISSANCE IN SOUTHWEST LIAU-TUNG. 95 
Ta-ku-shan series.—The advanced metamorphism of these quartzites, 
marbles, and schists indicates that they are older than the unmetamor- 
phosed Paleozoic rocks. This view is corroborated by von Richthofen, 
who observed the Sinian limestones and sandstones lying unconformably 
upon the metamorphic series.* In northern China proper we distinguished 
two sedimentary systems of Pre-Cambrian age, and it may be supposed 
that the Ta-ku-shan system is the representative of one or the other of 
them. In comparing it with the Hu-t’o series, we find that the Ta-ku-shan 
is more severely metamorphosed, and lacks the flinty limestones which 
are so characteristic of that series. The Ta-ku-shan rocks more nearly 
resemble certain portions of the Wu-t’ai series of Shan-si, which, like 
them, contains marble and quartzite associated with schists; but the 
data are not yet sufficient to establish a correlation. 
Yung-ning sandstone.—Von Richthofen’s observations remain the 
principal data available in regard to the stratigraphic relations of the 
Yung-ning sandstone. He describes it as underlying the Fu-chdéu series, 
which in turn he found beneath strata containing Upper Cambrian fossils. 
The Fu-chéu series, which von Richthofen correlated with his Tung-w6n 
(our Man-t’o and Kiu-lung) seems to represent Middle Cambrian; but 
the Fu-chéu strata do not include any of the red rocks elsewhere so charac- 
teristic of the Man-t’o or Lower Cambrian. The Yung-ning sandstone is 
red and apparently occupies, in relation to the Fu-chéu, the position 
which the red Man-t’o holds with reference to the Kiu-lung. On this 
basis we provisionally regard the Yung-ning as a local and probably 
littoral phase of the Man-t’o formation. 
Fu-chou series.—This series, like the Yung-ning, has failed to yield 
any fossils. Von Richthofen says that it rests upon the Yung-ning sand- 
stone and underlies dark Upper Cambrian limestones, which are in turn 
followed by the so-called ‘‘Kohlenkalk’’ (the Tsi-nan limestone of Shan- 
tung).— The dark Cambrian limestones were identified by means of 
numerous fossils. He considered the Fu-chéu series equivalent in age to 
his ‘‘Tung-w6n Schichten” near I-chéu-fu in Shan-tung.[ This is a suc- 
cession of reddish shales and sandstones, with thin-bedded nodular and 
oolitic limestones. Judging from our own studies in Shan-tung, I infer 
that the sequence of the Tung-w6én-ho contains portions of the Man-t’o 
shale and the Kiu-lung limestones, but the section has been interrupted 
by faults and igneous intrusions, so that the order of succession is unreliable, 
In that phase of the Fu-choéu series, which occurs along my route in Liau- 
tung, there is little to remind one of either the Man-t’o or the Kiu-lung 
* China, vol. 11, pp. 98, 100. tIbid., pp. 79, 80. {Ibid., pp. 187, 188. 
