Page:Quarterly Journal of the Geological Society of London, vol. 25.djvu/223

 down, and which form a continuation of those at Suichang. This series contains in the district at least one coal-seam, which is worked at a place called Yishan, some six miles distant from the river ; the coal is slightly bituminous, but soft and friable, and does not appear to occur in quantity ; the seam is said to be about 3 feet thick, and dips towards the west at a slight angle. The coal rests on a bed of whitish clay containing the remains of roots, and is capped with a black shale in which occur plentifully remains of Sigillarioe (apparently S. reniformis), as well as leaves resembling in their striae those before spoken of. The series seems to be overlain at no great distance by the succeeding formations ; but a hasty visit some four years ago did not give me time to note the sequence satisfactorily. At Hingkwoh, situated in the same district, but more to the east, a bed of similar coal is said to occur ; the district is surrounded by the earlier rocks of Suichang.

At Nanking, however, the lower Tungting beds are succeeded by a very important series of newer rocks, which, as occurring preeminently in the Chung-shan outside the north-east angle of the city, may conveniently be named the Chung-shan series. Following the system adopted in the nomenclature of the lower beds, they may be subdivided as follows : —

4 Grits and coarse yellow sandstones   unknown containing beds of coal 3. Quartzose conglomerate              About 100 feet. 2. Red flagstones                      " 1800 " 1. Coarse red grits and sandstones     " 500 "

I do not know the lateral extension of the series, which assumes some importance in this district ; it seems to extend to some distance to the south and west of Nanking, and to be repeated to the north of the river Yangtse, where, however, as yet, I have had no opportunity of becoming acquainted with the rock-masses. I am disposed, however, to look upon it as the representative of the newer coal- beds of North China, at least until further investigation has proved their dissimilarity. South of Nanking, in a range of detached hills between that city and Taiping-fu, rising to some 1000 feet over the plain, another series of yellow quartzose grits and conglomerate occurs ; the conglomerate is remarkable from containing fragments of the Tungting limestones, as well as pebbles of quartz rock, which can only be referred to that formation : this I am disposed provisionally to look upon as the summit of the series ; but as I have never met with a similar formation in other localities, this is of the less importance to our present purpose.

The lower beds of the Chung-shan series offer few peculiarities. They lie unconformably over the edges of the Tungting rocks, as may be readily observed on the road leading from the Taiping-men at Nanking, and contain occasional fragments of the older rocks imbedded in them. The lowermost rocks are very irregularly deposited, but are followed by a system of fine-grained dark red sandstones (No. 2), which attain a considerable thickness. The series within the immediate district of Nanking (fig. 5) ranges from the neighbourhood