572 Reports and Proceedings — Geological Society of London. 



Geological Society of London. 



The opening meeting of the Session was held at Burlington Hovise 

 on the evening of November 8th, 1905. J. E. Marr, Sc.D., F.R.S., 

 President, in the chair. 

 The President announced that the Council at their meeting on 



June 28th last had passed the following resolutions : — 



1. "The Council desii-e to record on their Minutes an expression of their deep 

 regret at the death ot their distinguished Treasurer, and of their grateful recognition 

 of the loyal and effective services which for so long a series of years he has given to 

 the Geological Society as Secretary, President, Treasurer, and Member of Council." 



2. " That a copy of this resolution be forwarded to Mrs. Blanford, with an 

 expression of the deep sympathy of the Council with herself and family." 



The following communications were read : — 



1. " The Coast-Ledges in the South-West of the Cape Colony." 

 By Professor Ernest Hubert Lewis Schwarz, A.R.C.S., F.G.S. 



The following coast-shelves have been recognized by the author 

 in Cape Colony : — 



NATIVE 

 NAME OF SHELF. WESTERN; MIDLANDS. EASTERN. TERRITORIES, 



ft. ft. ft. ft. 



Cyphergat 5000-6000? 5000-6000? .')450? — 



Sterkstroom 3500-4000? 4000? 4406? 4500? 



Kentani 2500 2500 



DeYlugt 1500 1000 1500 1500 



Uplands 700 463 467 600 



Bamboes Bay.... 50-100 200 151 50-200 



Sea-level — — — — 



Agulhas —600 



The most striking of these is the Upland shelf, which extends from 

 Caledon to Port Elizabeth. It is cut by deep gorges into narrow 

 ridges or ' ruggens,' but at a height the level tops of these ridges 

 can be observed. The surface is in places covered with superficial 

 deposits, cemented boulder -deposits, gravels, and sandy clays, 

 hardened at the surface into ironstone or fresh-water quartzite. 

 The author considers that this shelf cannot have been formed as 

 a peneplain, but by marine denudation. On the 150-200 foot 

 plateau there are deposits with marine shells, and in a depression on 

 its top the evaporation of rain-water produces a large quantity of 

 salt. The rock-shelf under the Cape Flats appears also to have been 

 cut by the sea. The Agulhas Bank seems to consist of a succession 

 of ledges, but it is not known whether further shelves extend beyond 

 its margin. Taking the ledges together, the continent would appear 

 to have been subject to lifts of 600 or 700 feet, with intermediate 

 halts and set-backs. The author introduces the term ' absolute 

 base-level of erosion' "to express the ocean-floor, including the shelf 

 or level of erosion cut by the surf and off-shore currents that came 

 near the water's edge when the depression of the present land- 

 masses commenced." The author compares the shelves of Cape 

 Colony with those described on the European and American sides of 

 the North Atlantic, and he places the 'absolute base-level of erosion' 



