GEOLOGY OF CENTRAL SHEN-SI. 317 
According to Pére David,* who noted the rocks at Shi-ts’tian-hién 
while descending the river in 1873, similar reddish sandstone and con- 
glomerate outcrop near Ch’6ng-ku-hién on the upper Han. Beyond this 
brief mention, however, we know of no previous description of the Shi- 
ts’iian formation, in the Han valley. Weare inclined to regard it as equiv- 
alent to the conglomerate and sandstone described by von Richthofent 
and later by Léczy{ from northern Ssi-ch’uan. 
Von Richthofen’s section is given on a subsequent page. There is 
nothing in the lower members A and Br and 2 resembling the strata at Shi- 
ts’iian-hién, but the strata B3 and 4 are essentially the same. The heavy 
conglomerate B3 marks a change of climatic or topographic conditions, if 
not an unconformity, and it is probable that a stratum which contains 
pebbles of the Paleozoic rocks should overlap upon them. On this com- 
parison we regard the Shi-ts’tian sandstone as probably equivalent to B3 
and 4 and assign it toa later Mesozoic age than the ‘“‘lower Jura”’ or Triassic 
of von Richthofen’s section. 
PLEISTOCENE. 
The Huang-t’u formation of northern China was not seen along our 
route across the Ts’in-ling-shan and through the Han valley. Remnants 
of alluvial soil remain here and there, on cut terraces in the mountains, 
but they do not constitute aformation. Recent river alluvium and gravels 
are not extensive along the streams, where they flow in canyons. Only in 
the basin of Hing-an-fu did we observe a considerable deposit of fluviatile 
material. It consists of gravels carried by the Han, and is not very 
recent, as the pebbles of crystalline rocks, which it contains, are generally 
decayed. Glacial deposits do not occur, and even the lofty summit of the 
Ta-pai-shan (12,500 feet, 3,750 meters), exhibits no topographic features 
suggestive of glaciation. A fuller account of the Pleistocene features is 
given in the chapter on the physiography of southern Shen-si. 
* Journal de mon 3me Voyage d’Exploration dans |’Empire Chinois, vol. 1, p. 49. 
+ China, vol. un, p. 603. 
t Ergebnisse der Reise des Grafen Béla Széchenyi in Ost-Asien, vol. 1, p. 439. 
