44 



given in Plate IV, page 71. Both these meetings were attended 

 by some forty members, and much interest was excited by the 

 important and controversial nature of the subject. It may be noted 

 that the views upheld by Dr. Ord were substantially those 

 advanced by Professor Bonney in his subsequent address as 

 President of the British Association for the Advancement of 

 Science, on " The Ice Age in Western Europe," at the Sheffield 

 meeting in August, 1910. 



An important paper was read on February 17th, 

 The Rivers on « The Rivers of the South of England," by 

 of the South h. St. Barbe, Esq., of Lymington. Some forty 

 of England. members attended, and the lecture was illustrated 

 bv diagrams and maps. Commencing by a reference to the dis- 

 crepancy generally exhibited by the rivers of this district between 

 their present volume and the dimensions of their valleys, the 

 streams appearing to have greatly shrunken in volume from what 

 they must have been when their valleys were excavated, the lecturer 

 stated that two causes could be adduced in explanation. The first 

 cause was a change of climate, following the different elevation of 

 the land in former times, which, with the extensive forests which 

 then covered the country, produced a far greater rainfall. The 

 second cause was the retreat and melting of the great ice-sheets 

 which covered so much of the country during the glacial period. 

 The modern theory of the mode of origin and formation of rivers, 

 now generally accepted, was then explained, as advanced by 

 Professor W. M. Davis, of Harvard University, and the meaning of 

 the terms " consequent," "subsequent," and of the " beheading" of 

 rivers was described. The effect of various earth movements, with 

 the anticlines, synclines, and escarpments produced by them was 

 next dwelt upon, and their action in determining the course of 

 various rivers was explained. Examples were adduced from the 

 present courses of the Thames, Bristol Avon, Blackwater, and 

 Wey. The importance of the Chalk formation to rivers in the 

 South of England was pointed out, and the cutting short of rivers 

 by the sea in our coast districts received careful attention. 



On April nth, Dr. W. T. Ord read a paper on "The 

 The Great Great Purbeck Faultj and the Geology of the 



Purbeck Fault. Purbeck Hills." The lecture was illustrated by 

 maps and diagrams. Referring to the unique section of the chalk 

 strata and the great fault displayed in the magnificent cliffs of 

 Ballard Down, seen by every visitor on the steamers to Swanage, 

 the lecturer explained the former conditions of the chalk range of 

 Purbeck Hills, and their geologically recent connection with the 

 Needles and chalk downs which formed the back-bone of the Isle of 

 Wight. Their relation to the Hampshire basin and the more 

 northerly ranges of chalk hills was next described. An account of 

 " Faults," and their origin, was then given, and finally a lucid 

 description of the great Purbeck thrust fault followed. The lecture 

 was illustrated by a number of large diagrams. 



