4 GEOLOGICAL MEMOIRS. 



Inoceraraus mytiloides. Ammonites Rhothomagensis. 



Cuvieri ? Mantelli. 



Ananchytes ovatus. falcatus. 



Micraster arenatus. Fleuriausianus ; and others. 



cor-anguinum ; &c. Scaphites aequalis. 



Gryphaea coluraba. Baculites baculoides. 



Nautilus triangularis. Turrilites costatus. 



Ammonites varians. Gravesianus; and others. 



Woolgari. 



This is a mingling of the fossils of the white and the chloritic 

 chalk, contained in numerous strata constituting a well-developed 

 terrain, which ought, indeed, from its uniform characters and the 

 relations of its parts to be regarded as single and indivisible. 



At the geographical limits of this terrain we find cropping out 

 two strata of sandstone (of a green colour from the grains of glau- 

 conite abundantly disseminated in the rock), which separate it from 

 the underlying compact yellow limestone. 



These two strata of green sandstone are naturally disconnected 

 from this terrain, — Istly, by the distinct separation at their line of 

 contact ; 2ndly, more especially by the fossils that characterise 

 them. 



The first of these strata contains at the Madonna di Laghetto, the 

 plain of Eza, and the Rayet near Monte Calvo the characteristic 

 Ammonites of the Gault : the fossils are, — 



Ammonites Lyellii. Ammonites Beudanti. 



mammillaris. latidorsatus. 



Roystianus. Discoidea subuculus ; 



Delaruei. and others. 



interruptus. 



The second stratum affords characteristic lower neocomian fossils. 

 It is to be recognized by the little flattened oval oolitic grains of 

 hydrated iron ; and is characterized at Monte Calvo, S. Lorenzo di 

 Turbia, the Fosse di S. Ospizio, Toretto, Col di Revello, &c., by 

 the following fossils : — 



Ammonites Astierianus. Ammonites radiatus. 



cryptoceras. angulicostatus ; 



difficilis. and others. 



Leopoldinus. Crioceras Emerici. 



heliacus. Belemnites dilatatus. 



Ixion. subfusiformis ; and others. 



These two strata almost always occur in separate localities ; they 

 have a development of from one to a few metres, and lie conformably 

 on the compact yellow limestone. 



Major Charters has visited some of these localities, and, to my 

 satisfaction, has arrived at the same conclusions. 



Jurassic rocks. — Beneath these green sandstones lies the dirty- 

 yellow compact limestone, more or less dolomitic, which forms the 

 flanks and the crest of the principal mountains above Nice, and 

 along a considerable tract of country in Liguria to the West. 



This limestone is considerably developed ; and, without overstep- 

 ping the truth, it may be estimated at above 1000 feet in thickness. 



