372 Obituary Notices of Fellows deceased. 



on the Denudation of the Weald." This memoir appeared in the 

 twenty-first volume of the "Quarterly Journal of the Geological 

 Society." The peculiar and seemingly anomalous system of drainage 

 in the Wealden district of the south-east of England where the rivers, 

 instead of following what would appear to be their natural course from 

 west to east into the North Sea, cut their way through narrow gorges 

 in the North and South Downs and flow north and south into the 

 Thames and the English Channel respectively had long attracted the 

 attention of geologists. To account for the phenomenon, Hopkins and 

 others had maintained that the longitudinal fold of the Weald must 

 have been accompanied by a series of transverse fractures, along which 

 the rivers had eventually cut their courses. Murchison and Lyell 

 maintained, however, that the main portion of the denudation of the 

 Wealden anticlinal could only have been effected by marine agency. The 

 publication in 1862 of Jukes' luminous memoir " On the Eiver Valleys 

 of the South of Ireland " had thrown doubt on these earlier conclusions 

 of geologists, and led at the same time to a clearer recognition of the 

 part played by subaerial and river denudation , and Jukes' views had 

 found a zealous advocate in the late Sir Andrew Ramsay. Le Neve 

 Foster and Topley, by a study of the nature and composition of the 

 gravels which form terraces of the Medway Valley up to the height of 

 over 300 feet above the existing river, were able to show that their 

 deposition could not possibly be ascribed to marine action, but must 

 have been due to the operation of the river and its tributaries when 

 flowing at higher levels. Further than this, they were able to demon- 

 strate that all the principal rivers of the Wealden area, now running 

 northward or southward, must have begun to flow, before the east and 

 west valleys had originated, through the wearing away of the softer or 

 least resistant strata by subaerial action, and that, as the level of the 

 rivers had been gradually lowered, the remarkable gorges through the 

 North and South Downs, by which the rivers now find their outlet, 

 had been slowly cut down. 



These interesting conclusions have now been universally accepted by 

 geologists, and it is not too much to say that the important memoir of 

 Le Neve Foster and Topley, supporting as it did, by reference to a 

 very well-known area, the masterly researches of Jukes in Ireland, has 

 proved the starting point of those valuable investigations concerning 

 the origin and development of river systems, which, commenced in this 

 country, have been carried out with such striking results by the 

 geologists and geographers of the United States. It is interesting to 

 note that Le Neve Foster's share in this work had been accomplished 

 before he reached the age of twenty-four. 



In 1865 Clement Le Neve Foster resigned his post on the Geological 

 Survey and became Lecturer to the Miners' Association of Cornwall 



