1835.] Scientific Intelligence. 79 



the mine, and has been introduced into the lias formation at the 

 period of the upheaving of the Pyrenean granite. The saccharoid 

 limestone of the Valley of Sue owes its texture to its position in 

 contact with the granite. 



The limestone contains Pecten equivalvis ; Terebratulae and 

 Belemnites. 



VI. — Geological position of the Campan Marble. By 

 M. Dufrenoy. (Ann. des Sciences, xxviii.) 



This marble forms a subordinate bed in the transition formation of 

 the Pyrenees. It consists of nodules of limestone, agglutinated with 

 clay slate of a greenish or reddish colour, presenting an amygdaloid 

 appearance. The nodules are Nautili, of which the spiral form may 

 frequently be detected. Dufrenoy considers the formation contem- 

 poraneous with that of Plymouth. Near the village of Sirach, in 

 the Valley of Prades, besides Nautili, several fossils peculiar to the 

 transition formation appear. Prades is situated on granite. Over 

 the granite, clay-slate reposes containing felspar veins and red oxide 

 of iron. This slate is green, passes insensibly into a mixture of lime- 

 stone, and then into the marble. In the limestone which succeeds 

 are formed Orthoceratites, Terebratulae, and Encrinites, similar 

 to those of Dudley. 



It is remarkable that the strata which contain the nautili are at a 

 distance from the granite, and that in proportion as we approach 

 this rock, the nodules loose their organized character. At a little 

 distance at Tuchan, slates resembling those of Sirach occur covered 

 by the coal formation, where impressions of vegetables appear abun- 

 dantly. The coal is worked at Segur and Quintillan. 



VII. — Effect of Gases on Vegetation. By M. Mac aire. 

 (Ann. des Sciences Naturelles.) 



M. Macaire introduced some plants of Euphorbia, Mercurialis, 

 Senecio, Sonchus &c. into vessels along with chloride of lime in 

 the morning. When evening arrived the plants had not sufFered, 

 and the odour of the chlorine was as strong as at first. Next morning 

 they were found withered, the smell of chlorine had disappeared, 

 and was replaced by a very disagreable acid odour. The same result 

 was obtained on repeating the experiment several times. 



Nitric acid withered the plants during the night, but in the day 

 time merely rendered some of them brown coloured. 



Sulphurretted hydrogen produced no alteration when light was 

 present, but destroyed them in the night, by the absorption of the gas. 



Muriatic acid gas acted in a similar manner. 



VIII.— Notices of the Natural History of Egypt in 1832. 

 By M. Roux. ( Ann. des Scien. Nat.) 



The only species of Helix which he found was the irregularis, in 

 the vicinity of Alexandria. He discovered two new species of 



