Geological Society. 515 



when alive, must have measured five and tv^^enty feet around the body, 

 and about one hundred and thirty feet in length. 



A letter was read from Charles Stokes, Esq., F.G.S., F.R.S., to W. J. 

 Broderip, Esq., Sec. G.S., explanatory of three drawings of JEc/iini, repre- 

 senting, 1. A specimen of Galerites albo-galerus, Lara., from the chalk, 

 in which the plates of the mouth, consisting of five pairs, are preserved 

 in situ; 2. A Cidaris, also from the chalk, in which portions of the 

 plates of the mouth and the teeth are visible : they are displaced, but ex- 

 hibit a system quite analogous to that of the recent Cidaris ; and, 3. A 

 Cidaris from Stonesfield, in which the anal plates are in the best 

 preservation. 



Kovemher 7 and 21. — A paper On the Geology of JVice, by H. T. De 

 la Beche, F.R.S., L.S., and G.S., was read, in which the authour, after de- 

 scribing the situation of Nice, enters into a detailed account of the dilu- 

 vium and the strata in its neighbourhood. 



The diluvium (if indeed it can be so considered) is peculiar ; in gene- 

 ral it takes the form of breccia, either diffused irregularly or occupying 

 clefts ; appearing however in both situations to be intimately connected. 

 Most of the diffused fragments correspond mineralogically with the rocks 

 on which they rest ; some few are rounded, and seem to have been trans- 

 ported from a distance. The cement varies in hardness 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 Mediterraneum 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. 



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 pebblesj in the blue Hmestone of the 



