62 Geological Society : — 



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 Dum- 

 fries, Scawfell granite (Eskdale of Mackintosh) was the most 

 abundant grauite ; then came grey granites from Dumfries ; syenite 

 from Buttermere, which occurred all over the area described, and up 

 to 1200 feet on the Macclesfield Hills ; and syenite from Cannock 

 fell. Other probable identifications were also named. The whole 

 series of rocks from the Silurian to the New Red Marl were repre- 

 sented 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.S., 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 Cly 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 moutonnee aspect. 

 The evidence of glacial action is classified under the following 

 heads : — (1) erratics ; (2) Boulder-clay ; (3) shattered and con- 

 torted 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 dolomitic conglomerate, Lias, and 

 chalk flints. These, in one district, are derived from 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 sometimes 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. Pagan. 



(4) Grooved and striated surfaces are preserved under favour- 

 able circumstances. A full description is given of a number of 

 instances, the direction of the striae being recorded, as well as the 

 fall in feet per mile from the summit of the Beacons. The author, 

 in summing up his observations, comes to the conclusion that the 

 erratics in the Eglwysilian and Caevan group were probably, as a 



