74 DR TT: J. TERU ON 
quartz, and the smaller ones were angular, while the bigger ones tended to be more 
rounded. 
3. Upper Boulder-Clay and Rubbly-Drift.—The sands and gravels are in many 
places covered by a yellowish-brown boulder-clay, quite different in character from the 
bluish boulder-clay which underlies them. This Upper Boulder-Clay is sometimes 
fairly tough, and is generally much more stony than Lower Boulder-Clay. It varies 
very much in thickness and character. Inland it often only occurs as a thin covering 
a few feet deep, but on the coast, where the best exposures are seen, much greater 
depths are attamed. Sometimes it is a tumultuous unstratified till, with boulders of 
all shapes and sizes scattered pell-mell throughout the matrix. At other places—and 
it has more of the character of a rubble-drift, 
and as seen in section, has the appearance of an agglomeration of coarse and more or 
it may be at no ereat distance away 
less angular débris, showing a rude kind of bedding. It is evident that most of it 
consists of material which has been re-arranged to some extent, and afterwards modified 
by sub-aerial agencies. It is impossible to separate the more typical unstratified 
boulder-clay from the rough semi-stratified clayey and sandy rubble-drift. The 
included boulders are derived in the main from the rocks of the district, but 
many far-travelled stones are also found, and these will be discussed in the next 
section. Ice-scratched stones are fairly common. ‘These are usually sub-angular, 
with blunted angles and rounded edges. Rounded waterworn stones are also common, 
especially in the re-sorted rubbly-drift. No traces of marine shells are seen in the Upper 
Boulder-Clay and Rubbly-Drift. On the coast it is found capping the rocky cliffs at 
places, and in the bays fine sections, sometimes over 20 feet deep, are exposed. The 
foreshore is often covered with big boulders derived from the neighbouring cliffs. As 
the sea is now gradually gaining on the land, the cliffs of drift on the coast are being 
continually undermined, and: the included stones and boulders are washed out and 
strewn over the shores. The beaches on the bays are rich in boulders and stones of 
rocks foreign to the district. ‘These have undoubtedly been derived from the cliffs of 
drift, which are constantly undergoing a process of degradation owing to the action of 
the waves and of sub-aerial agencies. 
By far the best exposures of these upper deposits are shown on the coast-line of 
the St David’s promontory. Figs. 4 and 5 (Plate) represent sections seen in Whitesand 
Bay, and give a very good general idea of the appearance of these Upper Drift deposits. 
Fig. 4 shows a section of the cliff near the north end of the bay. Here the cliff is 
about 20 feet high and consists entirely of drift. At this spot the drift is a 
typical till or boulder-clay, showing no bedding, but full of stones and boulders, big and 
small, which are scattered confusedly through it. Most of the boulders are angular and 
sub-angular, and some are well glaciated. A few rounded pebbles and stones also occur. 
The boulders are mostly of local rocks, though some erratics are seen. Loose sandy 
soil occurs at the top. At the base the rock does not appear, but the shore is covered 
with stones derived from the cliff. A few yards further north slaty rock is seen 
