400 RESEARCH IN CHINA. 
PSAMMITES. 
Purplish-gray sandstone, No. 51.—This sandstone is probably a part of 
the Po-shan coal-bearing formation. A stratum, several feet in thickness, 
was found associated with grayish tuffs and basaltic flows, about 2 miles, 
3 kilometers, northeast of Yen-chuang. 
A rather fine-grained compact sandstone of a dark purplish-gray color. 
Most of the rock consists of rounded and subangular quartz grains which 
have been enlarged peripherally and cemented together by quartz subse- 
quently deposited upon them. The less common constituents are grains of 
flint and iron ores; and the dark color of the rock is occasioned by the 
presence, in the cement, of limonite, hematite, and other dark impurities. 
Impure calcareous sandstones, No. 38.—Forms thin strata interbedded 
with gray sandy shales in the middle member of the Sin-t’ai series. The 
sandstone is used locally in the manufacture of millstones. Specimen 
collected 4 miles, 6.5 kilometers, south of Sin-t’ai-hién. 
A dull-gray friable sandstone of rather coarse texture. The thin 
section shows the rock to be composed of sand-grains of various sizes, 
cemented together by cloudy calcite, together with a subordinate amount of 
clay-like matter. The grains are either subangular or fairly well rounded. 
The majority of them are quartz, but there are several additional varieties, 
which are given approximately in the order of their abundance as follows: 
limestone, feldspar, flint, decayed ferro-magnesian minerals, and iron ores. 
CARBONATE ROCKS. 
Pale pink limestone, No. 41.—This peculiar limestone is a rather uncom- 
mon phase of the red beds of the Sin-t’ai formation. The limestone 
occurs as strata interbedded with the red shales in the upper part of the 
series, 3.5 miles, 5.5 kilometers, west of Sin-t’ai-hién, Shan-tung. 
An aphanitic creamy pink limestone with irregular or conchoidal 
fracture. It includes numerous small seams and irregular cavities which 
are partially or wholly filled with drusy calcite crystals. 
Although the mass is exceedingly dense yet it is visibly granular, 
the cavities mentioned having been filled with calcite deposited in the 
form of concentric linings. The greater part of the rock is without definite 
structure, but here and there one sees certain indistinct features which 
appear to be bits of fossils. There is nothing, however, which is recog- 
nizably organic. 
Rocks OF IGNEOUS ORIGIN. 
The igneous rocks which are associated with the Carboniferous strata 
in Shan-tung vary from such intermediate types as dacites and syenites 
to ultrabasic lavas; rhyolites were not observed. By far the most common 
