Geological Society. 555 



result is a work which should prove useful and extremely interesting: 

 not only to the novice, but also to the specialist. After some 

 introductory chapters dealing with wave-motion, radiation, the 

 general principles of electrostatics and electrodynamics, the 

 generation and transformation of currents, the production of 

 electric oscillations, resonance, and Hertz's experiments, the author 

 briefly traces the beginnings of wireless telegraphy, and gives an 

 extremely clear account of modern forms of: detectors. Then 

 follow methods of obtaining syntony, and finally an account of such 

 practical systems as are actually in use at the present day. We 

 can strongly recommend this excellent little work to all interested 

 in the fascinating subject with which it deals. 



LY. Proceedings of Learned Societies. 



GEOLOGICAL SOCIETY. 



[Continued from vol. xiii. p. 763.] 



May 15th, 1907.— Sir Archibald Geikie, D.C.L., Sc.D., Sec.R.S., 

 President, in the Chair. 

 HE following communication was read : — 



T 



On the Origin of certain Carion-like Valleys associated with 

 Lake-like Areas of Depression.' By Frederic William Harmer, 

 E.G.S., E.R.Met.S. 



In glaciated regions, as shown by Prof. P. P. Kendall, the in- 

 vasion of a district by an ice-sheet would tend to obstruct the 

 natural drainage, producing lakes, of which the outflow might take 

 place over the advancing ice, between the ice and the hillsides ; 

 or it might escape laterally, in a direction at right angles to the 

 longest diameter of the lake and to the course of the pre-existing 

 stream. Overflow-channels would assume a gorge-like character, 

 t and would present a comparatively-recent appearance. During 

 the Glacial Epoch the North-Sea ice appears to have invaded the 

 plain of the Witham and the valleys of the Welland, Nene, and 

 Ouse, overriding also the higher land separating them ; the Tees 

 ice-stream moved up the Trent basin to the vicinity of Derby 

 and thence, inosculating with the Derwent glacier, up the Soar 

 Valley towards Leicester and Rugby ; the Irish-Sea ice passed into 

 the northern part of the basin of the Lower Severn ; ice from the 

 Brecknock Beacons passed towards the Bristol Channel and, com- 

 bined with Irish-Sea ice crossing Pembrokeshire from St. David's 

 Head towards Cardiff, may have caused the accumulation of 

 sedentary ice in the Severn Valley. After considering the case 

 of Lake Pickering and the Malton Gorge as a typical example, 

 the author passes on to Lake Shrewsbury and the gorge at Iron- 

 bridge. Preglacial drainage of the Upper Severn and Vyrnwy was 

 probably northwards ; when a Glacial lake was first formed over 

 the Cheshire plain it may have drained towards the Trent, pos- 

 sibly by Rudyard and Madeley ; when these gaps were closed, the 

 lowest outlet seems to have been towards the south, and the 

 Severn Gorge at Ironbridge was cut. The caiion of the Camlad 

 at Chirbury, known as Marrington Dingle, appears to have been 



