Geology of Gibraltar 203 



and garrison, he made a complete geological survey of the 

 Rock and the neighbouring part of Spain. They had after- 

 wards gone along the coast of Africa from Ceuta to Cape 

 Spartel, staying several days at Tangier. Just outside the 

 gateway of that town, which leads to the sands, they had 

 found in a cliff, close to the sea at high water, contorted 

 strata of shale and sandstone, overlain by coralline sand 

 and beds of quartz-sand and gravel, looking rather like the 

 English Crag. In the half consolidated material of this 

 they discovered, lying on the denuded surface of the shales 

 and sandstones, the tooth and a fragment of the jaw of 

 Elephas antiquus. 1 This, the forerunner of the existing 

 African elephant, had not hitherto been found on that 

 continent, though it occurs in the bone-caves of Gibraltar, 

 in England, and in other parts of Europe. He also made 

 some remarks on the direct communication between Africa 

 and Europe in comparatively recent geological times. 



Conversation then turned to the apes on the Rock of 

 Gibraltar, which Professor Ramsay said were ' pretty 

 numerous/ Dr. Sclater observed that when he was there 

 in 1861, they were reduced to three females, and he had 

 urged the introduction of others lest the breed should 

 become extinct. 2 



May 3ist, 27ist meeting. Mr. Huggins exhibited speci- 

 mens of artificial corundum, recently made by M. Feil, of 

 Paris, the well-known maker of optical glass. They consist 

 of about 90 per cent, of alumina, fused, under certain con- 

 ditions, with small quantities of oxides to give the colour 

 of rubies, sapphires, and amethysts. Examination with 

 polarized light distinguishes them from the naturally formed 

 stones, but they have the same hardness, lustre, and other 

 physical properties. The subject was resumed on June 2ist, 

 when Sir W. Grove said that M. Becquerel many years ago 

 had shown him a pill-box full of small rubies which were 



1 See, for an account of the geology of Gibraltar, A. C. Ramsay and 

 Jas. Geikie, Q.J.G.S. xxxiv. pages 505-539. The tooth is the right ultimate 

 tipper molar. It and the section are figured on page 514. 



2 See Vacation Tourists, 1861, pages 206, 207. 



