32 GEOLOGICAL RESEARCHES IN 



have followed from the Te Hai passes beneath us, and continues south to Tatung (fu) 

 and the Sankang Ho ; it is well watered and fertile. 



Crossing this southern promontory of the lower plateau the road descends into 

 the valley of Kwantung (pu), a depression occupied by another tributary of the San- 

 kang Ho, and lying between the lower plateau and the Barrier range. This range 

 and a spur from it, form the southern and eastern limits of the valley, and the 

 lower plateau forms the northern side, while to the west it is open. 



A quarry about half way up the edge of the plateau presents a good though 

 limited section in the volcanic formation. In this quarry two beds are visible — a 

 lower one of crystalline lava, which, toward the top, becomes porous and passes 

 into a true scoria, and an upper bed of more compact lava. Crevices extending 

 through both these beds are fiUed with a calcareous segregation. 



The terrace deposit sweeps from the valley of Fungching around the southern 

 spur of the lower plateau, into the valley of Kwantung, from the centre of which it 

 rises rapidly up to the sides of the mountains, filling their ravines, to a height of 

 several hundred feet above the middle of the valley. 



From the mountains forming the northeastern side a low spur juts out, narrowing 

 the valley, and in the space between the point of this spur and the southern wall 

 of the valley there is another of those remarkable watersheds to which I have seve- 

 ral times alluded. The terrace deposit rises from the west to form this bar (though 

 without reaching a height at all comparable to that to which it rises on the moun- 

 tain sides) and falls off again toward the southeast. 



Crossing this bar, and descending toward the southeast, we traverse the Barrier 

 range by a deep and narrow gorge about eight miles long, through which flows 

 a small stream which, taking its rise in the northeastern part of the vaUey of Kwan 

 tung, empties into the Yang Ho. 



In this gorge the range is seen to consist of crystalline metamorphic schists, 

 chiefly gneiss, hornblende gneiss, hornblende schist, and hypersthenite, in strata 

 varying in trend between N. N. W. and N. N. E., the dip at the two ends of the 

 defile being toward the centre. 



The terrace deposit occurs in this gorge and its side ravines, high above the 

 stream, and on emerging into the great valley of Yangkau it is seen rising from the 

 plain with an unbroken surface high up the sides of the Sierra north of the Yang- 

 kau valley, whUe south of the mouth of the defile it exist only as terraces several 

 hundred feet above the plain. The terrace deposit extends from here down the 

 valley of the Yang Ho to form the plains and terraces of the enlargements of the 

 valley at Siuenhwa (fu) and Shachung. But it is not confined to the present river 

 systems, for east of Tienching (hien) it caps the lower part of the ridge between the 

 valleys of Yangkau (hien) and Hwaingan (hien) forming a plateau of loam several 

 hundred feet above the valleys. 



Following the road from Yangkau to Tienching, we have on the north the Barrier 

 range, a rugged sierra of which the barren peaks must be from 2,000 to 3,000 feet 

 high, above the valley. Along the line where the terrace deposit terminates on the 

 steep flank of the sierra, extends the now ruined Great Wall of China, with its 

 towers and parapets, till at a point opposite Tienching it crosses the mountains to 



