PEREZ GEOLOGY OF NICE. 5 



The agents which have metamorphosed it — sometimes into gyp- 

 sum, sometimes into dolomite — have not so obscured its stratification 

 but that it may be seen with difficulty in a few places. 



To M. Sismonda's reasoning on the original cause of the production 

 of the gypsum of this limestone, I will add a fact of some weight ; 

 namely, the alteration which the rocks of the chloritic chalk lying 

 above this limestone have undergone in the gypsum pit of S. Rosalia, 

 where, although very much deranged and altered, they can still be 

 recognized ; and I note this fact as opposed to the conclusions which 

 might be drawn from the perhaps not too exact observation of M. Tchi- 

 hatcheff, who described his having seen the gypsum lying in strata 

 above the compact limestone at Monte Morone. 



The disturbances which this terrain has suffered render it some- 

 what difficult to recognize the order and arrangement of its parts. 



It appears to me possible to divide it into three portions ; — the 

 uppermost is characterized by numerous Zoophytes (as at the Faro, 

 where it is soon covered up by the neocomian sandstone) ; — the 

 middle division is very dolomitic, and especially contains NerincEa ; — 

 the lowest contains the majority of the Ammonites, of which the 

 following is a list : — 



Ammonites biplex. Ammonites flexuosus. 



multiradiatus. Koenigii. 



tortisulcatus. subfascicularis. 



To the above list may be added others which are referable to the 

 section "planulati," but the species of which are not recognizable. 

 Other fossils * are : — 



Belemnites (indeterm.). Terebratula globosa, Sow. 



Nerinsea Wisurgis, Roem. maxillosa, Sow. 



Terebratula perovalis, Sow. 



Also several Echinodermata, which are regarded as Jurassic by M. 

 E. Sismonda, who has also collected from this limestone some inde- 

 terminable fragments of an Apiocrinite and a Pentacrinite. 



These fossils were collected at the foot of Monte Calvo in the 

 Valley of S. Andrea, at the foot of the hill of Rovello, at S. Ponzio, at 

 Monte Albano, and at the hill of Turbia near S. Lorenzo. In some 

 of these localities we collected them in company with Major Charters. 



The supposed absence of Jurassic fossils in this limestone, — its 

 having analogous mineral characters with the neighbouring rocks of 

 the Cheiron, and other reasons derived from position, — and espe- 

 cially the [presumed] affinity of some of its fossils with the neocomian, 

 were the reasons that induced M. Sismonda to regard it as neoco- 

 mian, and to remove it from the Jurassic series, with which De la 

 Beche and Bucklandf had placed it. Some geologists indeed are still 

 inclined to take this view. 



* I am indebted to Baron von Buch for the determination of the Jurassic Am- 

 monites, and to M. Bellardi for that of the other fossils of this terrain, 

 t Trans. Geol. Soc. 2 ser. vol. iii. p. 183 et seq. — Transl. 



