348 



THE GEOLOGIST. 



Fossil Teichechus. — " The teeth of the sea-horse are frequently found 

 in many places of the Arctic turf-marshes bordering on the Frozen Sea, 

 and they are so fresh that they are sold in commerce for ivory. In the 

 Gulf of Pensehin there was one of these teeth dug out that was 8^ lbs. in 

 weight, and another in Kamtchatka weighing h\ lbs. (P. Nordmann, 

 Beytr.) A tooth of a bluish colour was found at the mouth of the Tagil." 

 — Extract from Georgi, (N'at. Hist. Russia) ' Beschreibung des Hussischen 

 Eeichs,' vol. iii. p. 591, by S. J. M. 



Salt Deposit at New Iberia. — The rock-salt at this place in Louisiana 

 is of the most extensive and wonderful description, and of great purity. One 

 American account says : — " Imagine the granite quarry of Massachusetts, 

 or the marble quarry of Vermont, to be solid deposits of pure rock-salt, 

 clear and transparent as so much clear white ice in one solid inexhaustible 

 mass underlying the earth, and you will then acquire an imperfect idea of 

 the vastness of this salt formation." 



Natural Formation of Carbonate of Soda. — In the ' Pharmaceutical 

 Journal' for July, Dr. Haines, of Grant College, Bombay, gives an account 

 of the natural production of carbonate of soda in the neighbourhood of 

 Aden. It occurs in the form of irregular, colourless, partly crystalline 

 masses, apparently of two distinct portions : one a brilliant, confusedly 

 crystalline mass, amongst which the angles of cubical crystals could be 

 observed ; the other, a white amorphous substance, of a greasy feel and 

 soapy odour, very similar to crude borax. By analysis, the composition 

 was given as : — ■ 



Neutral carbonate of soda ........ 51'05 



Common salt, with traces of sulphate of soda and 



chloride of magnesium . 21*94 



Water and organic matter 19'66 



Sand 4 "3 5 



100-00 



Captain Playfair, Assistant Political Resident at Aden, states that this 

 substance is found all along the coast to the east of Aden to an extent of 

 perhaps ten miles, and its quantity is practically unlimited. It is. usually 

 found in hollows behind (or bej^ond) high-water mark to which the sea- 

 water has access by percolation. There is no demand for it at present, 

 but some months ago, sixty to seventy camel-loads a day were brought 

 into Aden, and met with a ready sale at 2| rupees per ten maunds (equal 

 to two shillings a hundredweight). The only use made of it is to mix with 

 snuff, to increase the pungency ; rarely, too, it is used for washing clothes. 

 It is variously called by the Arabs Dukduha, Hurlca, and Kara. 



From the valuable paper published by Mr. H. J. Carter in the Trans- 

 actions of the Bombay Branch of the Royal Asiatic Society, on the 

 Geology of Arabia, it appears that the whole of the south-east coast of 

 Arabia, from Rus-al-Hacl to Bab-ul-Mandib, is capped Avith nummulitic 

 limestone, pierced at frequent intervals with basaltic effusions, and in 

 many places elevated so as to form lofty and abrupt cliffs, in which, be- 

 neath the limestone, other formations are visible. As a result of this for- 

 mation, the shingle on the coast consists mainly of limestone ; and although 

 no specific description of the coast immediately to the east of Aden has 

 been given, there is no reason to doubt that the same peculiarities prevail 

 there. It is then to the percolation of sea-water through a stratum of 

 fragments of limestone that we must attribute the production of the car- 

 bonate of soda, by which percolation, probably, a partial interchange of 



