562 Notices of Memoirs — Col. Playfair — Algerian Marbles. 



Clay, Corallian, etc, beds whicli have been proved above Oxford 

 Clay in the Subwealden Boring, to the great thickness of over 

 1600 feet. 



We are therefore faced v^ith a great northerly thinning of the beds 

 below the Gault, a fact agreeing in the main with the evidence given 

 of late years by various deep wells in and near London. 



Three other deep borings have been made or are being made near 

 Chatham, all of which have passed through the Chalk into the Gault, 

 and one has gained a supply from the sand beneath. 



The practical bearing of the Chatham section is, however, to 

 enforce the danger of counting on getting large supplies of water in 

 the London Basin from the Lower Greensand, by means of deep 

 borings at any great distance from its outcrop. 



Even if Lower Greensand occur at all in such places, it will 

 probably be in reduced thickness, and therefore with reduced water- 

 capacity. 



III. — On the Ee-discoveey of Lost Numidian Maebles in 

 Algeria and Tunis. 



By Lieut.-Colonel R. L. Playfaik, H.M. Consul- General 

 for Algeria and Tunis. 



THE author explained that the name itself was a misnomer, as 

 they are not found within the limits of Numidia proper, but in 

 the province of Africa and in Mauritania. Most of the ' Giallo antico ' 

 used in Kome was obtained from Simittu Colonia, the modern Chem- 

 ton, in the valley of the Medgerda, the quarries of which are now 

 being extensively worked by a Belgian company; but the most 

 remarkable and valuable marbles are found near Kleber, in the pro- 

 vince of Oran, in Algeria. There, on the top of the Montague Grise, 

 exists an elevated plateau, 1600 acres in extent, forming an un- 

 interrupted mass of the most splendid marbles and breccias which 

 the world contains. Their variety is as extraordinary as their beauty. 

 There is creamy white, like ivory ; rose colour, like coral ; Giallo 

 antico ; some are as variegated as a peacock's plumage ; and on the 

 west side of the mountain, where there has been a great earth- 

 movement, the rock has been broken up and re-cemented together, 

 forming a variety of breccias of the most extraordinary richness and 

 beauty. 



Colonel Playfair exhibited specimens of the principal varieties, 

 to prove that his descriptions were not exaggerated. The beauty of 

 these marbles has been recognised by the Trustees of the British 

 Museum, who are now mounting the sculptures of the Parthenon and 

 the Mausoleum on basements of them. Specimens may also be seen in 

 the Mineralogical Koom of the British Museum, at South Kensington. 



The marble mountain belongs to Signer del Monte, of Oi'an, and, 

 although it is not being worked as it ought to be, blocks can be 

 obtained at a cost of about £18 per cubic metre, ready for shipment. 



