﻿CXX PROCEEDINGS OP THE GEOLOGICAL SOCIETY. [May I908, 



Society. But to some of the contributions which have appeared 

 in our Journal a brief allusion may be made. One of the earliest 

 and most important of these was the conjoint memoir by Topley 

 & Le J^eve Poster 'On the Superficial Deposits of the Medway 

 Valley, & Eemarks on the Denudation of the Weald.' ^ This 

 essay greatly cleared the ground, by showing how little relation 

 there may be between the lines of valleys and the positions of 

 faults, how fatal are the objections to the theory of marine erosion 

 as applied to the valleys of the South-East of England, and how 

 convincingly all the accumulated evidence points to long-continued 

 subaerial denudation by rain and rivers. Eamsay had, shortly 

 before, published similar conclusions in his ' Physical Geology & 

 Geography of Great Britain,' ^ but he did not communicate any 

 paper on the subject to the Society until February 1872, when 

 he read one on 'The Eiver-Courses of England & Wales.' In 

 perusing this suggestive essay we can note the broadening of 

 the author's views on the whole subject, and the growth of 

 his vivid realization of the fact that before the history of the 

 present valley-system of a country can be interpreted, a prolonged 

 investigation is necessary, not only into the geological structure 

 of the ground as it is now to be seen, but also into the evidence of 

 the extent to which the surface of the land was once covered with 

 material that has since been removed by denudation. His later 

 papers communicated to the Society contain further applications 

 of the same methods of enquiry.^ If some of their data were 

 perhaps too indefinite and uncertain to warrant even the tentative 

 outlines of physiographical restoration which he based upon them, 

 the papers were at least eminently suggestive and did good service 

 by fostering an interest in the subject, even where they may not 

 have greatly advanced its development. 



Of all Ramsay's contributions to this branch of geological 

 research, that which attracted most notice at the time, and has 

 given rise to the largest amount of discussion since, was his 

 famous paper on the glacial origin of lakes.* As the subject is 



1 Q. J. vol. xxi (1865) p. 443. 



2 The first edition of this work appeared in 1863, the second in 1864. 



' ' Physical History of the Ehine Yalley ' Q. J. vol. xxx (1874) p. 81 ; ' How- 

 Anglesey became an Island' ibid. vol. xxxii (1876) p. 116 ; ' Physical History 

 of the River Dee ' ibid. p. 219. 



* Q. J. vol. xviii (1862) p. 185. The glacial origin of lakes by the accumu- 

 lation of moraines or other forms of drift had been previously noted: see, 

 for example, T. Codrington, Q. J. vol. xvi (1860) p, 345. 



