18 J. S. Lee — Recent Ice-action in N. China. 



of glaciation in the hills further north-east. This is borne out bv 

 fact. 



About 3"5 miles north-east of Sha-yuan-ling a roundish knoll 

 rises above the loess plain with a small temple, the Shan-shien- 

 miau, standing on its top as a conspicuous landmark. A small 

 valley runs along the northern foot of the hill in a south-easterly 

 direction. At Nau-pei-kou, a few hundred yards north-east of the 

 Sha-shien-miau, and about 1 mile north of the Pei-tso village, 

 the trend of the valley is slightly deviated by a hill-spur pro- 

 jecting from the south. Here, bedded green and buff sandstones, 

 belonging to the uppermost part of the coal-bearing series, are well 

 exposed. In the bottom of the valley parallel grooves are seen 

 on the surface of an extremely hard sandstone in situ. The surface 

 appears to be on the whole horizontal but locally undulatory, 

 showing decisively that it has been planed or abraded by some 

 powerful agent. All of the grooves run north-east, except for a 

 minor set which cuts the former at a very small angle. 



The sandstones dip regularly south-east. No sign whatsoever 

 can be detected pointing to the existence of a thrust or a fault. 

 One of the abraded beds in the bottom of the valley exhibits a 

 partially striated, concave surface with its striated part inclined 

 towards the north-east ; while the unstriated part, namely, 

 the north-eastern part, tends to curve upward towards its 

 north-eastern edge. Such a state of things could not possibly 

 have been brought about by a dislocation of the bedded rocks, 

 nor could it be attributed to the hypothetical expansion and 

 consequent slip of an overlying stratum. 



It may be reasonably questioned that if a glacier did actually 

 occupy the valley during a recent geological time, how could it have 

 left traces of its movement across the valley instead of along it, 

 since the latter would be a far more natural course 1 To answer 

 this question we need to know the nature of the valley and the 

 topography of the surrounding country. The valley, or more pro- 

 perly the ravine, is only of very small size, being 20 to 30 feet wide 

 at the bottom and not much deeper than 200 feet from the bottom 

 to the top of the hill on the south. Therefore an ice-sheet of 

 moderate thickness could have indiscriminately buried the whole 

 area, and made its movement quite independent of the local 

 irregularities of the floor. The occurrence of strange blocks and 

 fragments of rocks on the top of the hill of the Shan-shien-miau, 

 which stands much higher than the hill just referred to, and the 

 heavy abrasion that the bedded rocks of Nau-pei-kou must have 

 gone through are facts which combine to demonstrate the con- 

 siderable thickness of the ice. 



The boulder-bed of the Sha-yiian-ling, as already mentioned, is 

 quite loose and in a way conformable with the overlying loess. 

 A priori it is a geologically recent deposit. If the quartzite pebbles 

 occurring in the upper part of the boulder-bed be genetically 



