THE GLACIAL DEPOSITS OF NORTHERN PEMBROKESHIRE. 61 
Referring to some of the shallow valleys and peculiar bays seen in Pembrokeshire, Sir 
AnprEW Ramsay, in his essay “On the Denudation of South Wales and the adjacent 
Counties of England,” contributed to volume i. of the Memoirs of the Geological Survey, 
says (p. 329): ‘‘ In numerous instances valleys opening to the sea end in bays, and it 
will be found that not infrequently the headlands on either side of these bays were 
composed of comparatively unyielding materials. Depress the land, and these valleys 
become arms of the sea; raise it, and the bays become a continuation of the valleys. 
If Pembrokeshire were elevated but 60 or 70 feet, Milford Haven would become a 
shallow valley of this nature, with occasional pools or small lakes in its hollows, through 
which would wind the water now flowing into the haven.” And similarly, if the county 
was depressed but 60 or 70 feet, the valleys at the lower part of their course would form 
sea-inlets like Milford Haven, and Barry and Dinas would be separated as islands from 
the mainland. It is practically certain that movements of elevation and of depression 
have taken place within comparatively recent times, but it is a difficult problem to 
ascertain the extent and duration of these movements. 
The land of the St David’s promontory was long ago described by GriraLpUs 
CAMBRENSIS as a “stony, barren, unimprovable territory, undecked with woods, 
undivided by rivers, unadorned with meadows, exposed only to winds and storms.” 
Since his time the land has yielded somewhat to the continuous treatment of genera- 
tions of farmers, and a great part of it is now under cultivation. But much rough 
uncultivated moorland still remains, which in places is overgrown with gorse, and 
sometimes shows a boggy nature. Such are the commons seen round about St David's, 
and also further east. Parts of them are occupied by shallow sheets of water, as at 
Trefeithan common and Dowrog common. As a rule these commons are of a clayey 
nature, and in places some peat formation is seen. Peat becomes more evident in the 
country lying to the south of Fishguard and south-west of the Precelly hills, and it is 
dug even right up on the Precelly hills themselves. The country from Newport to 
Cardigan is well cultivated for most part. 
Throughout the area under consideration in this paper much of the soil is of 
a distinctly sandy nature. Hence the land is very dry and needs much rain. It is an 
old saying in this part of Pembrokeshire, that ‘‘ in summer rain every day is too much, 
and every second day too little.” 
The greater part of the land is covered by a blanket of superficial material, which 
may all be included under the name of Drift. This is somewhat variable in character, 
but near the surface a sandy element seems to predominate. However, as traced 
laterally, the sand often passes abruptly into clay or clayey loam, and vice versa. This 
drift near its upper part is usually stuck full of boulders and rock-fragments of all 
kinds, and of all shapes and sizes. Good sections are seen along the coast in some of the 
bays, but it is very rarely that one meets with a good exposure inland. Smoothed, 
polished, and ice-scratched boulders can be picked out of the drift in plenty, and occur 
throughout the district. It is more difficult to meet with examples of striated and 
TRANS. ROY. SOC. EDIN., VOL. XLI. PART I. (NO. 4). 11 
