RECONNAISSANCE IN SOUTHWEST LIAU-TUNG. 87 
streams, brought about by this subsidence, has initiated a period of aggra- 
dation. All of the streams are now engaged in silting up their valleys, 
and are pushing back the heads of the inlets as their flood-plains are 
extended sea-ward by constant additions of material. The rapidity of this 
progress is strikingly indicated by the present situation of certain towns, 
which, within three or four centuries, were seaports, but which are now 
some miles from the coast. One of these, Siung-ytié-chéng, is said to 
have been a port of entry of considerable importance during the Ming 
dynasty (A. D. 1368 to 1625); the city is now nearly deserted, and the 
head of its former harbor lies 4 miles to the west of it. 
GEOLOGY. 
INTRODUCTION. 
Observations made in the course of a rapid journey, which did not 
permit extensive digressions from the road, must necessarily include 
errors and uncertainties. In this particular trip the difficulties were 
somewhat increased by the frequent recurrence of sandy flats and by the 
prevalence of a mantle of soil over the bed-rock. It was, therefore, fre- 
quently impracticable to determine the limits of such formations as were 
recognized, and the entire failure of all efforts to find fossils left me in 
doubt as to questions of age. The following section, therefore, is indefinite 
as to thickness, limits, and geologic age; it represents merely a reason- 
able interpretation of such facts as are available :* 
5. Volcanic rocks: intrusions (and possibly extrusions) of basalts, porphyries, etc. 
4. Fu-chou series: earthy sandstones, quartzites, argillaceous limestones, and shales, mostly of 
green, gray, and purplish colors. Probably of Cambrian age. 
3. The Yung-ning sandstone: earthy sandstones, sandy shale, and conglomeratic sandstone— 
all of reddish or brown colors. Probably Lower Cambrian. 
2. The Ta-ku-shan series: quartzite, marble, and slates. Probably Algonkian. 
1, Gneissic complex: gneiss, schists, granite, etc., including the granite near Siung-yué-ching. 
Probably Archean. 
STATEMENT OF OBSERVATIONS. 
Gneissic complex.—Rocks of the basal complex were encountered in 
two localities only. The first exposure occurs about 4 miles, 6.8 kilometers, 
northwest of Pu-lan-tién and is something more than a mile in breadth. 
The rock is biotite-gneiss of rather fine grain, into which have been 
intruded dikes of gray granite associated with veins of pegmatite and 
quartz. A single large dike of basalt was found cutting through this 
complex, and as it is not metamorphosed it is probably of much younger 
age. This exposure is obscured along its southern border by sand and 
* The difficulties in the way of making a satisfactory study of this area in the course of a rapid jour- 
ney are eloquently set forth by von Richthofen in his report. (China, vol. 11, pp. 109, 110.) 
