116 Transactions of the South African Philosophical Society. 
Above the road, in the same ravine, is a smaller section showing 
horizontally bedded shales. These shales are soft, friable, dark blue 
shales weathering white, similar to the beds usually found overlying 
the conglomerate in the Prieska and Hope Town divisions. From 
their present position it is probable that they were deposited in a 
hollow in the conglomerate, for they are at about the level of the 
middle portion of the sections below the road, and there is no 
evidence of a fault which might have dropped them down. The 
occurrence of sands and muds in depressions in glacial tills is 
frequently described in modern or recently glaciated areas of the 
northern hemisphere. From the character of the conglomerate just 
described it is a legitimate inference that it is a true till formed by 
land-ice, and was not deposited on the floor of a lake or sea. 
A very similar but less exposed section is seen near the Brak 
River, where it enters the Orange River some 15 miles north-east of 
Prieska village. 
North-west and west of Prieska village there are several outliers 
of the conglomerate lying undisturbed in depressions in the ancient 
rocks forming the Doorn Bergen. These are of great interest in 
proving that the main contours of that range were in existence at 
the time of the deposition of the conglomerate. Many of the smaller 
ravines have been cut through both the conglomerate and older rocks 
quite irrespectively of the surface features which existed before the 
deposition of the conglomerate. But in the large valleys of the range, 
such as that on Nauw Gekneld and T’Dyzega on the north-east, and 
the Uitspansberg valley on the west, the position and form of the out- 
liers proves that the recent valleys have been re-excavated along the 
lines of old ones which were filled with conglomerate. 
The conglomerate is seen on the surface over a very wide area in 
the southern part of the Prieska division, and between Beer Vlei and 
Hope Town, but owing to the absence of river channels natural 
sections are never seen. ‘The presence of the conglomerate is always 
indicated by the numerous weathered-out boulders scattered over the 
veld, often so abundantly that one cannot put a foot down without 
touching one or more of them. Very many of these boulders show 
numerous striae, especially on their flat sides, but the scratches are 
not so fresh on them as on the stones taken directly from the 
conglomerate, owing to the action of the weather. Some of the 
boulders lying on the veld must weigh several hundred pounds. 
In spite of the absence of natural sections, the character of the 
conglomerate is to be seen in the water-furrows dug by the farmers. 
The best sections we saw were on the western side of the Groot 
Modder Fontein pan (Doorn Fontein), and on Jonker Water. Unfor- 
