66 DR T. J. JEHU ON 
At Cardigan the height of the boulder-clay above sea-level is under 50 feet. 
Between Cardigan and Dinas this blue clay is seen in patches underlying small tracts of 
moorland, and it attains a height of nearly 600 feet a little south of Pen-Creigau, where, 
at a short distance below the road to Cardigan, it may be seen, though the exposures 
are very poor. 
Just south-west of Dinas, near the roadside, clay-pits occur on Rhos-Isaf showing 
a depth of 6 feet. The same stiff, compact, bluish boulder-clay is here seen, full of com- 
minuted shell-fragments. Boulders are fairly common, mostly ice-worn and scratched, 
but some water-worn. One example of a slaty rock showed not only fine striz but 
a wide groove smoothed out by ice action. The clay gets darker as traced downwards, 
but the bottom is not seen. Workmen stated that it reaches a depth of at least 15 
feet, and occasionally a thin seam or stratum—no more than half an inch in diameter— 
of fine gravel is said to occur. But no trace of bedding occurs in the clay. It is 
capped for 2 feet by a yellowish clay with boulders. The pits are 240 feet above 
sea-level. Small exposures are seen in some of the fields on Dyffryn farm, about a 
mile south of Goodwick. Owing to drying and weathering, it is of a light bluish-gray 
colour, and is here full of fragments of the local lavas and tuffs. Most of this farm 
is underlain by this clay. A little further south, in a field belonging to Drim farm, is a 
small pit of a similar character. No shell fragments were to be seen in these exposures. 
Similar tough bluish boulder-clay is seen in clay-pits on Tregroes moor, at a height 
of over 250 feet. In fact, in all the moors lying to the south of Fishguard, with the 
exception of those found on mountain-slopes, this boulder-clay can be found, but it 
is unfortunate that there are no deep pits or good sections to be seen. But the 
engineers of the Great Western Railway are making borings in this neighbourhood for 
a tunnel, and they very kindly supplied the writer with all the information in their 
possession which might be of interest. A boring has been made at Trebrython farm, 
to the south-west of Tregroes moor, and about 150 yards from the railway. In the 
boring the following succession was obtained :— 
5 feet of earthy clay. 
5 feet of yellowish clay, with rock fragments. 
10 feet of a somewhat tough ereyish-blue clay. 
Slate rock. 
The greyish-blue clay is the Lower Boulder-Clay, and it is seen that it only attains 
a thickness of 10 feet here. The yellowish clay may be partly the bluish clay weathered, 
but most probably consists for most part of the equivalent of the Upper Boulder-Clay. 
The boring is made at a height of nearly 300 feet above sea-level. About three- 
quarters of a mile down the railway towards Goodwick is a railway cutting passing 
through part of the superficial deposits, and a boring has been made here also. A full 
section of this cutting and boring is given on another page, but it may be mentioned 
here that typical tough blue boulder-clay is there shown which attains a depth of 
