CHINA, MONGOLIA, AND JAPAN. 13 



chambers extending nearly in a straight line. The first two of these only were 

 visible, the entrance to the third having been closed by an imperial order, owing 

 to a party of visitors having lost their way and perished. 



These chambers are connected by passages, so small that they can be entered 

 only by creeping on hands and knees. Their longest axis is at right angles to 

 the strike of the strata, and forms a considerable angle with the dip. The floor is 

 covered with stalagmite, which, in the centre of one chamber, seems to be at least 

 forty feet thick, and is connected with the roof by immense columns of stalactite. 

 Like many large caverns in China, this one is sacred to Buddha, of which deity 

 there is a well executed high-relief sculptured in the wall of the entrance ; and the 

 small passages have been worn and polished by the knees of pilgrims durmg 

 centuries. 



I looked in vain at the face of the rock at the entrance, for some signs of a crack 

 corresponding to the plane of these chambers. 



Some of the deep and narrow ravines of the surrounding hills, seem to have been 

 formed by the caving in of similar caverns. 



In parts of the empire, these caves abound in fossil bones, which are excavated 

 and used in medicine, under the name of " dragon's bones," " dragon's claws," etc. 



This limestone, forming, as it does, the floor of the Coal measures, appears, 

 surrounding the difterent basins of these, in highly inclined beds, forming as it 

 were a narrow frame, or, having a gentler dip, it occupies a broader space. 



Pm-phyry Conglomerate. — In the mountains that border the Wangping basin on 

 the north and west, there are extensive masses and dykes of porphyry, which have 

 raised and cut through the limestone in aU directions. From the detritus of this 

 intrusive rock, the beds of the lower Coal measures at Chaitang, which are equivalent 

 to those marked No. 3 in the table, seem to have been formed. The reason for 

 supposing this, is, that as we approach the northern edge of the Chaitang basin, 

 we find the porphyry conglomerate underlying, in the form of a flat boss, the beds 

 forming the lower half of No. 5 which are eminently characterized by two peculiar 

 rocks, that marked as " compact green argillite" and the still lower ones, " green 

 qnartzose conglomerate." Further on we find, that the porphyry conglomerate 

 contains interstratified beds of sandstone. The fragments that form this extensive 

 member of the Chaitang series, are, for the most part, derived from the masses of 

 porphyry nearest at hand. Thus near Chingtai they are chiefly green felsitic 

 porphyry, similar to that forming dykes in the limestone at Hiamaling, a few miles 

 distant, while, along the Hun river, red and green varieties predominate, intrusive 

 masses of both kinds occurring in the neighborhood. 



Fragments of limestone and quartz are frequent in the porphyry conglomerate, 

 and would seem to characterize its upper portion. Thus I have indicated in the 

 table two distinct varieties, though perhaps on insufficient grounds. 



This conglomerate furnishes an important page in the history of the Coal measures 

 in this region. It shows us that there had been an elevation of the limestone, 

 perhaps caused or accompanied by the intrusion of the porphyries, before the 

 overlying rocks were deposited. The presence of fragments of limestone, quartz. 



