THE VALE OF CLWYD. 238 
In the New Red are lines and lenticular beds of conglomerate, 
composed of limestone pebbles, probably derived from the 
Mountain Limestone, which occurs not far off. It is then much 
like the brockram of the Eden Valley; at other times the 
fragments are all of Silurian. The ground is steep and rough, 
and the denudation rapid, so that the section varies much from 
year to year, and the small lines and bands of conglomerate 
cannot always be seen. 
Fic. 11. 
Section near old quarry opposite Cilowen, St. Asaph. 
(Scale, 4. feet to 1 tnch.) 
a, False bedding. 
6. Pebbles in fissures running obliquely to face of rock. 
c. Joints. 
I have known some curious cases in which one might be 
deceived by the accidental occurrence of pebbles, which have 
got in along lines of fracture in the rock. For instance, in a 
cliff near Cilowen, near St. Asaph, in which the rock consists of 
a false-bedded, homogeneous, softish red sandstone, crossed by 
two principal sets of joints (see fig. 11.) Down the middle of 
the section, and partly following the joints, runs what appears 
to have been a small open fissure, which has got filled with nests 
and lines of pebbles. These sometimes strike off into the lines 
of bedding, where they look exactly like contemporaneous 
conglomerate ; but they do not follow it far enough to lead one 
to think that they were all derived from, and originally belonged 
to bands of conglomerate in the New Red. The pebbles are all 
such as might be derived from the Grauwacke (Silurian and 
Cambrian) to the West. ‘They are flat pebbles, varying from 
1% inch diameter down to sand. There are broken pebbles, 
and a few angular fragments. Quartz occurs but rarely. 
The real explanation is that the principal fissure runs just 
behind the surface, being inclined at a small angle to the face 
of the rock. So that as the face of the rock gets cut back, the 
debris in the irregular fissure gets exposed, and the irregularities 
of the fissure coincide generally with the bedding and cross 
joints. 
OLDER PLEISTOCENE. 
GLACIAL. 
First let us run over the main facts. On the hills all round 
the Vale of Clwyd striations on the solid rock are clearly seen 
in several places, always running in an easterly direction, 
generally a little N. of E. 
Close to the cart track leading from Aclwyd Uchaf up the 
well-wooded hill known as Fron Haul, about 2 miles N.E. of 
St. Asaph, and running down the eastern slope near the top of 
Cz 
