36 Reports and Proceedings. 



or Brazil ; but the new fields had yielded no less than five stones 

 exceeding this weight within that time. He had models of many. 

 There was one of 56 carats, and another of 83 carats, which arrived 

 last year, and produced a stone of great beauty, weighing 46^ carats. 

 This was the largest in the market, and was valued at £20,000. It 

 had been named the " Star of South Africa." The three sketches here 

 given show the exact size, a representing the face, h side view, 

 and G the back of the stone, as cut. It is now in the possession of 

 Messrs. Hunt & Eoskell, who have kindly promised to allow any 

 one who wished to see it. The lecturer proceeded, by means of 

 diagrams, to explain the technical terms used in describing the 

 forms in which the crystals of diamonds were found, and described 

 some peculiarities of the stone by which it might be readily distin- 

 guished from other crystalline minerals of somewhat similar appear- 

 ance. The diamond, although the hardest of substances, was one of 

 the most brittle; and it was probably owing to ignorance of this fact 

 and carelessness on the part of the diamond-seekers, that so many of 

 the diamonds brought from tbe Cape were broken. The principal 

 diamond-bearing districts at present discovered were the valleys of 

 the Vaal, Orange, and Eoit rivers. A great variety of other minerals 

 had been found in the same neighbourhood. The pebbles consisted 

 of rock crystal of different colours, and, together with agate, jaspers 

 (black, red, and ribboned), quartzite, garnet, spinel, peridot, and blue 

 corundum, were abundant. 



Discussion. — Mr.. Eawlinsoa drew attention to the great importance of diamonds 

 to the ai'tisan, the mechanic, and the engineer., 



Mr. Fordred observed that the discoverers of diamonds at the Cape frequently made 

 the mistake of placing a value exorbitantly high on the stones they sent over here to 

 be sold. 



Mr. Le Neve Foster said they made no allowance for the loss of weight in cutting. 



In replying, Professor Tennant said that only about ten j^er cent, of those found 

 were of the first water. In the large one of which he had spoken, weighing 56 carats, 

 there were three flaws; nevertheless £5,000 was offered to the finder while it was still 

 in the " rough." ' 



1 In the " Graaff Eeinet Herald" of October 29th, received by the last mail, it is 

 stated that one party found fifty-four diamonds, one of 160 carats, another 27, the 

 others smaller : altogether estimated at £150,000. 



Geological Society oe London, Novemlber 23, 1870. — Joseph 

 Prestwich, Esq., F.E..S., President, in the Chair. — 1. " On some 

 points of South-African Geology." — Part I. By G. W. Stow, Esq. 

 Communicated by Professor T. Eupert Jones, E.G.S. 



In this paper, which was illustrated by numerous sketches, sec- 

 tions, tables, and specimens, observations were made on the stratifi- 

 cation of the Jurassic beds of Sunday's and Zwartkop's rivers, 

 resulting from researches made by Mr. Stow, with the view of 

 determining the exact position of the several species of fossils 

 found at the exposures on the cliffs of these rivers, and from this the 

 sequence of the various beds. He indicated the existence of at 

 least nine separate fossiliferous bands, pointing out the relative 

 positions of the several Tr/^om'a-beds, Hamite-beds, Ammonite- 

 beds, etc. 



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