1818.] Edinburgh Traiisactions, Vol. VIII. Part II. 383 



VI. Sketch of the Geology of the Environs of Nice. By Tho, 

 Allan, Esq. F.R.S. Edin. 



From this paper it appears that the country in the immediate 

 neighbourhood of Nice is composed of limestone. Mr. Allan 

 distinguishes two different formations, which he calls first and 

 second limestone : the first he suspects to be transition, and the 

 second to be floetz, but he did not verify his suspicions by sa- 

 tisfactory evidence. The first limestone has a brown colour, a 

 compact texture, a conchoidal fracture, and, in general, shows 

 no appearance of crystallization, though sometimes it does. It 

 contains petrefactions, shells of different species, as cornu-am- 

 monis, pecten, and corraloids. Flint also occurs in it in nodules, 

 and seems sometimes to be in regular beds, as in chalk. Several 

 varieties of this limestone are described. The second limestone, 

 it would appear from the map which accompanies the paper, 

 lies chiefly in the valleys skirting the different rivulets. It has 

 the aspect, according to Mr. Allan, of having been tumbled doivn 

 from above the first limestone ; it lies in the most irregular 

 state, and is distinguished by those contortions and involutions 

 which have been so often described by the Huttonians with so 

 much delight. Had they examined the loose sand on the north 

 side of Edinburgh, they would have seen as many contortions in 

 it as in the rocks of St. Abbshead themselves. 



The second limestone is composed of strata varying very much 

 in thickness from a few inches to several feet ; its colour varies 

 from bluish to brownish grey ; sometimes it is hard and close 

 grained, with a splintery fracture ; sometimes its texture is 

 earthy, and it gives an argillaceous smell. It contains a pro- 

 fusion of shells. 



Besides these two formations, there is a vast deposite of al- 

 luvial gravel on the west side of Nice, and in other places in the 

 neighbourhood. This gravel consists of fragments of primitive 

 rocks, and contains mixed with it a vast quantity of shells, 

 many of them the very same species that still exist in the Me- 

 diterranean. 



The paper concludes with a catalogue of the shells found by 

 Mr. Allan near Nice : they amount to 225 species. This cata- 

 logue is drawn up by Capt. Brown, who ascertained the names 

 of the species ; and there are 33 species which he considers as 

 new. Of these he has given figures. 



VII. On certain Impressions of Cold transmitted from the 

 higher Atmosphere, with the Description of an Instrument adapted 

 to measure them. By John Leslie, F.R.S.E. and Professor of 

 Mathematics in the University of Edinburgh. 



Mr. Leslie is the philosopher to whom we are indebted for almost 

 all urn- knowledge of the radiation of heat. He himself, how- 

 ever, has never admitted the truth of the opinion that heat ra- 

 diates. According to him heat is nothing else than light fixed 

 in bodies ; it never can Leave a body at all without losing the 

 character of heat, and assuming that of light. What others 



