PROCEEDINGS 



OF 



THE GEOLOGICAL SOCIETY OP LONDON. 



1828—1829. No. 9. 



November 7. — The Society having assembled this evening for the 

 session : — 



The reading of a Paper " On the Geology of Nice," by H. T. De 

 la Beche, Esq. F.R.S. L.S. & G.S. was begun. 



Nov. 21. — The reading of Mr. De la Beche's Paper "On the Geo- 

 logy of Nice" was concluded. 



The author, after describing the situation of Nice, enters into a 

 detailed account of the diluvium and the strata in its neighbourhood. 



I. — The diluvium (if indeed it can be so considered) is peculiar ; in 

 general it takes the form of breccia, either diffused irregularly or oc- 

 cupying clefts : appearing however in both situations to be intimately 

 connected. 



1 . Most of the diffused fragments correspond mineralogically with 

 the rocks on which they rest ; some few are rounded, and seem to 

 have been transported from a distance. The cement varies in hard- 

 ness and colour with the substratum. Where the breccia reposes on 

 dolomite or light-coloured limestone, it is so hard as to be blasted by 

 gunpowder, is reddish and vesicular ; the vesicles being lined with 

 calcareous crystals. — Where it rests upon gray secondary limestone, 

 or on any of the tertiary beds, it is soft, friable, and almost white. 

 Between Ville-franche and Hospice, the substratum is a sand, full of 

 shells so like those of the Mediterranean as to have been called sub- 

 fossil : some of these shells retain traces of their native colour ; the 

 rest are bleached. This sand-bed at Ville-franche is ten feet at least 

 above the sea : at Baussi Raussi, where it descends to that level, the 

 breccia exhibits pebbles of serpentine as well as limestone : — the 

 limestone pebbles being perforated by lithodomi, and the cement con- 

 taining sub-fossil shells. None of these breccias contain bones. 



2. The other variety of the diluvium is lodged in fissures. A vein 

 on the south-east of the Castle Hill has its northern side perforated 

 by lithodomi, and yields two different kinds of pebbles, — in the blue 

 limestone of the lower part, and the magnesian above. This spot, 

 therefore, affords evidence of four distinct epochs. — 1. When the sea, 

 higher than at present, introduced lithodomi into the fissure. — 

 2. When the lower part of the fissure was filled with pebbles trans- 

 ported from a distance. — 3. When its upper part was filled with the 

 broken bones of animals, shells terrestrial and marine, and with frag- 

 ments, principally but not solely, of contiguous rocks. — 4. When the 

 sea attained its present level. 



