TRANSACTIONS OF SECTION C. G57 



[pRTDAr, SEPTEMBER 11. 

 The following Papers aud Reports were read : — 



]. On the Lakes of the Upper Etigadine. ^</ ANdre DelebecqUE. 



One of the most striking instances of a long depression forming a pass between 

 two valleys, and occupied by a series of lakes, is to be seen in the strip of land 

 which extends between St. Moriz and the Maloja. 



It is occupied by the four lakes of Sils, Silva Plana, Campfer, and St. Moriz, 

 ■with a depth of 71, 77, 34, and 44 metres respectively. 



The level of these lakes ranges between 1,771 and 1,800 metres. 



The lake of St. Moriz is obviously in a rock-basiu. 



As to the other three lakes, an opinion currently prevails which, though sup- 

 ported by the high authority of Professor Ileim, is believed by the author to be 

 unjustified. It is generally thought that the river Inn, weakened by the capture 

 of some of its tributaries by the river Maira, has been unable to sweep away the 

 deposits of the torrents descending from lateral valleys, and that consequently its 

 waters have been dammed up into the three lakes in question. 



An attentive survey of the region shows that, on the contrary, Ihese lakes for- 

 merly constituted a single sheet of water in a rock basin, which extended from 

 the Maloja to the village of Campfer, in both of which places ledges of gneiss are 

 visible, and that the lateral torrents, far from contributing to the formation of the 

 lakes, have partly filled them up by their deposits, and have divided into three 

 what was originally a single basin. 



The length of the original lake was remarkable, as it measured no less than 

 12 kilometres (7-J miles), and it must be borne in mind that, though moimtain 

 lakes are often very deep, their horizontal dimensions are generally limited. 



As to the origin of the lake, the author is of opinion that it caiwiot be 

 attributed to tectonic movements or to aqueous erosion, and that very probably 

 glacial excavation has come into play. 



2. On a Preglacial or Early Glacial Raised Beach in County Cork. By 

 H. B. Muff, B.A., F.G.S., and W. B. \Yeight, B.A., of H.M. Geo- 

 logical Survey. 



[Communicated with the permission of the Director of H.M. Geological Survey.] 



The existence of a raised beach formed, and probably elevated, before the 

 deposition of the boulder-clay has already been demonstrated in South Wales ^ 

 and Yorkshire." During the progress of the Drift Survey of the country sur- 

 rounding Queenstown Harbour a beach of similar age was observed along the 

 shores of the harbour, and was subsequently traced at intervals along the adjoining 

 coast of Waterford and Cork from Eallyvoyle Head, Dungarvan, to Clonakilty, a 

 distance from east to west of about sixty miles. 



The relation of this beach to the well-known submerged river valleys of the 

 south of Ireland is a point of considerable interest. The finding of glacial drift 

 and strife within the valleys led at once to the recognition of their preglacial 

 excavation, but the subsequent tracing of the raised beach beneath the bo^ulder- 

 clay along their banks showed that their submergence was also preglacial. 



The most persistent relic of the raised beach is a water-worn rock-platform, of 



' K. H. Tiddeman, M.A., F.G.S., ' On the Age of the Raised Beach of Southern 

 Britain as seen in Gower,' Rej}. Brit. Assoc, 1900, p. 760. See also Summary of 

 Progress of the Geological Survey of the United Kingdom for 1899, pp. 154, 155. 



= G. W. Lamplugh, F.G.S., ' Report of the Committee appointed for the Purpose 

 of investigating an Ancient Sea-beach near Bridlington Quay.'^e^. Brit. Assoc, 1890, 

 p. 375. See also Proc. Yorkshire Geol. and Polytechnic Society, 1887, p. 381 ; and 

 * The Drifts of Flamborough Htad,' (2uart. Jomti. Geol. Soc , xlvii. p. 384 



1903. uu 



