CHINA, MONGOLIA, AND JAPAN. 33 



extend northward to the high plateau. The southern side of the valley is formed 

 by a lower ridge, beyond Avhich higher mountains are seen, and over these the dis- 

 tant snow-capped^ peaks, or rather domes, of the range south of the Sankang Ho. 



Leaving the valley of the Yang Ho near Tienching, we cross over the terrace- 

 capped ridge before mentioned, into the valley of Hwaingan ^hien). To the north 

 of the road in crossing, and north of the whole valley of Hwaingan, the hills are 

 seen to consist of alternating strata of a bright red rock and of a harder rock, in 

 anticlinal and synclinal folds. The fragments brought by streams from the hill 

 forming the western part of the southern side of the valley, are gneiss and horn- 

 blende schist. 



FoUowmg the Hwaingan creek to the northeast, the road approaches, near where 

 it emerges into the valley of the Yang Ho, a fine section in the strata of the northern 

 hills. Besting on gneiss are strata of highly metamorphosed rocks, the continuation 

 of those we saw in the hills between Siuenhwa (fu) and Kalgan, and which for the 

 present may be called the Hwaingan beds. The valley of Hwaingan trends N. E. 

 by E., and this seems to be about the strike of the strata. In the exit into the 

 valley of the Yang Ho, the Hwaingan creek flows through a gorge formed by the 

 erosion, parallel to its axis, of an anticlinal ridge of the Hwaingan beds. 



From this point our road crosses the valley of the Yang Ho, and brings us again 

 to Kalgan. 



KALGAN TO SIWAN AND SINPAUNGAN. 



Leaving Kalgan the road runs in a northeasterly direction through a deep gorge, 

 with vertical walls, in the Kalgan trachytic porphyry, and its pluto-neptunian 

 deposits, as far as Ulanhada. At this village it leaves the valley of the main stream, 

 and turning into a tributary valley, winds with this through the mountains, following 

 an easterly course to the Roman mission of Siwan. For eight or ten miles we see 

 only the rocks of the Kalgan porphyry, but before reaching the village of Siyin'sz, 

 these are followed by the crystalline metamorphic schists, which in turn are suc- 

 ceeded, before we reach Siwan, by syenitic granite. This last is eruptive, dykes 

 of it traversing the metamorphic strata, and the main body often containing frag- 

 ments of the schists. This rock forms the mountains around and beyond Siwan. 



From Kalgan to this point, and beyond, the terrace deposit occupies the sides of 

 the mountains, and at Siwan its terraces form the sides of the valley to the height 

 of from 200 to 300 feet above the creek, and its vertical cliff's shoAV it to be a fine, 

 compact loam. In it the Chinese excavate their dwellings in suites of apartments 

 having doors, windows, and partition walls, all cut in the loam. The walls are 

 simply plastered over to prevent the dust from falling, and in this condition they 

 last as long, if not longer, than the ordinary houses built of sunburnt clay.^ In the 



' 26tli April, 1864. 



* These excavations are common wherever the terrace deposit occurs in Northern China. 



5 May, 1866. 



