46 eports and Proceedings—Geological Society of London. 
produced the planing and grooving of the rock and the red sand and 
rubble débris; then the ice melted back into local glaciers, and the 
submergence began. The low-level Boulder-clay and sands were, 
during a slow submergence, laid down probably at depths of from 
200 to 800 feet; and the author considers that all the phenomena can 
be satisfactorily accounted for by ordinary river-action and fraying of 
the coasts by the sea, combined with frost and ice due to a severer 
climate bringing down the materials of such river-basins to the sea, 
while icebergs and coast-ice sailed over, dropping on the sea-bottom 
their burdens of erratic stones and other materials from the mountain- 
districts of the north. He pointed out, also, that the great majority 
of the well-glaciated rocks were specially those that could be traced to 
the high lands. This fact was forced upon his notice after making a 
large collection of glaciated boulders and pebbles. Among the rocks 
he had been able to identify, with the help of Professor Bonney and 
Mr. P. Dudgeon, of Dumfries, Scawfell granite (Eskdale, of Mackintosh) 
was the most abundant granite; then came grey granites from Dum- 
fries; syenite from Buttermere, which occurred all over the area 
described, and up to 1200 feet on the Macclesfield Hills, and syenite 
from Cannockfell. Other probable identifications were also named. 
The whole series of rocks from the Silurian to the New Red Marl were 
represented in the low-level Boulder-clay ; a few flints also occurred, 
and one piece of what was believed to be chalk. 
‘the paper concluded with an Appendix by Mr. David Robertson, 
giving a list of the Foraminifera and other organisms found in the 
various beds of Boulder-clay in the Atlantic Docks, Liverpool. 
2. ‘On the Evidences of Glacial Action in South Brecknockshire 
and East Glamorganshire.””’ By T. W. Edgeworth David, Esq. 
Communicated by Professor J. Prestwich, F.G.8., F.R.S. 
The area which is included in this paper is about 200 square miles, 
extending north and south from the Brecknockshire Beacons to a line 
between Cowbridge and the mouth of the Rhymney, of which the Ely 
valley has been more particularly studied. Most of the rocks in this 
district, and particularly the Millstone Grit, retain traces of glacial 
markings. The whole area has a moutonnée aspect. ‘The evidence of 
glacial action is classified under the following heads :—(1) erratics; 
(2) Boulder-clay; (8) shattered and contorted rock-surfaces; (4) 
grooved and striated rock-surfaces. The first three obtain everywhere; 
but the last is confined to the coal-basin sandstones in certain localities, 
to the Millstone Grit at its northern outcrop, and to a small extent of 
Carboniferous Limestone to the north of the latter. 
(1) The erratics consist of Old Red Sandstone, of various members 
of the Carboniferous series, of dolomite conglomerate, Lias, and Chalk 
flints. ‘These, in one district, are derived trom Brecknockshire rocks, 
in another from Glamorganshire. 
(2) The Boulder-clay contains boulders which are sometimes 5 feet 
in diameter, generally smoothed, rounded, and striated. It is some- 
times 100 feet thick, and is found as high as 1200 feet above the sea. 
Many sections are described, and percentages of their contents given. 
(3) In certain districts the rocks are much shattered, so as to 
resemble a breccia, and Boulder-clay has been forced into this—as, for 
example, near St. Fagans. 
