NOTES ON GLACIAL ACTION IN BRECKNOCKSHIRE AND ADJOINING DISTRICTS. By F. T. HOWARD, M.A., F.G.S. LITERATURE. Sir R. I. Murchison The Silurian System. Rev. W. S. Symonds Observations on certain Drifts and Ancient River Beds of Siluria and South Wales. Brit. Assoc., Rep. 1865, and Geol. Nat. Hist. Repertory vol. i., p. 148, and Records of the Rocks. London: J. Murray, 1872. T. M. Reade Notes on the Southern Drift of England and Wales. Proc. Liverpool Geol. Soc., vol. iv., part iii., p. 216. 1881. Moraine of Llyn Cwm Llwch. Ibid, vol. vii., p. 270. 1894-5. Edgeworth David Evidence of Glacial Action in S. Brecknock and E. Glamorgan. C.N.S. Trans., vols. xiii. and xiv. 1882-83, and Q.J.G. S. xxxix., 39-53. H. Hicks On the Evidences of Glacial Action in Pembroke- shire and the direction of the Iceflow. Rep. Brit. Assoc., 1891, p. 500, and Geol. Mag., vol. i., p. igi. 1894. F. T. Howard and Notes on Ice Action in South Wales. C.N.S. Trans., E. W. Small vol. xxxii. F. T. Howard Lakes and Tarns of South Wales. C.N.S. Trans., vol. xxxii. T. Codrington Notes on a Submerged and Glaciated Rock Valley, recently exposed to view in Caermarthenshire. Abs. Proc.: Geol. Soc., 1901-1902, part i. PREVIOUS KNOWLEDGE. Sir R. Murchison in his Silurian System," referred in a general way to the glacial drift of Siluria," and showed that material carried from the hills of Central Wales occurs in deposits of varying thickness on the floors of the broader