the Tertiary, but what happened in West Wales is a mystery; the veil fell in the days of frogs and ferns, nor was it raised again until the land was inhabited by men, horses, and oxen. During the Carboniferous period the earth crust was palpitating; but the Pleistocene deposits show unmistakable signs of more serious convulsions. As is well known the highlands of North Wales are capped with gravels, containing forcign rocks and marine shells, proving that they have been dipped under ocean; we find this same drift formation in Pembrokeshire. Instances are to be seen on the cliffs in the Pencaer district, and on those near St. David’s. There is a very good specimen on the rocks above Marloes Sands, with a spur running off and meeting the Haven near Mullock Bridge. A fine section may be seen on Prendergast Hill, Haverfordwest, and no doubt many others. It is impossible to say whether this subsidence, and upheaval was a sudden catastrophe, resembling that which has in out days ruined Java, or the slow work of ages. Nature is a kindly mother to her children, and even in what appear to us as her angry moods, confers benefits on the sons of men. During the subsidence of the Carboniferous period, she harvested the coal crop for us the children of her old age. In the Pleistocene depression, flint stones were drawn into the drift, and on to the sea-shore. To us these are valueless, but to the first-born sons of man they represented a great deal: cutting implements, knives, axes, adzes, chisels, scrapers; boring tools, awls, and so on; weapons to be used in war and the chase; daggcrs, arrow-heads, spear-points, and other things too numerous for enumeration. Our predecessors easily dug flint from the soil for themselves when they dwelt on the chalk; but in lands like West Wales, destitute of flint, man in the stone age depended for his cutting tools, on the deposit left by this Pleistocene depression and upheaval. There is evidence to prove that this convulsion of nature occurred during a period of excessive cold, for we find that the shells imbedded in the drift are Arctic, and belong to species that still inhabit the Icelandic seas. After the land was again uplifted from the ecean bed, this severity of climate still continued, for the great mammals that have left the remains of their feasts and carcasses in the limestone caverns are in most instances of an Arctic type. The highlands of Scotland, Cumberland, Lancashire, and Wales were still enveloped in an ice-sheet, as is Iceland in our time.
The southern limit of this great glacier must have roughly followed the line of the South Wales Railway, from Clarbeston Road to Whitland. In Pembrokeshire, near Clynderwen Station, there is a very good section of boulder clay, or till, containmg angular erratic blocks of stone, some of considerable size polished and grooved by ice friction. Dr. Hicks, in a letter to the writer, states that he has found the same formation underlying the sunken forest in Whitesand Bay, St. David’s; and in many other parts of the county it may be studied. Organic remains are absent in this offscouring of ice-clad hills.
But in Pembrokeshire we find more interesting relics of the Pleistocene age than ice scratched stones. In the south-eastern corner of the county there are certain caverns in the Carboniferous limestone. The lower portions of these are filled in with red cave earth and breccia, (i. e., small fragments of limestone cemented together by carbonate of lime,) and this earth and stone is usually scaled down with stalagmite, formed by the drip of water through the limestone roof. In many of the caves, bones and tecth of great mammals are thickly packed in the red earth and broken stone. So wonderfully preserved are these boncs, that when the ignorant are assured they are in truth relies of an age so distant that its date cannot even be guessed at in years, our uninitiated one laughs you to scorn: "Why," he crics, "the bones of my grandfather, his ox and his ass, and all that was his, have crumbled into clay; and yet you tell me that this bone I hold in my hand may have been clad in flesh and muscle a million years ago; see, it is quite fresh, white, unpetrified, and looks not half-a-dozen years old.”
