1822.] Geological Societi/. 459 



bodies at present unknown in the Mediterranean Sea. 2. The 

 " Calcaire Subalpine '' of Brongniart. This rock is generally 

 greyish-white, of various shades ; it is almost entirely soluble in 

 nitric acid, and affords an excellent lime. Near the city, it is 

 stratified ; the beds are inclined at an angle of about 40° with 

 the horizon, and contain vast rents, crevices, and grottos. It 

 abounds in petrifactions, which are en)umerated by the author. 

 3. A third kind of limestone, incumbent upon those first men- 

 tioned, is of a grey colour, almost even fracture, and of consider- 

 able specific gravity and hardness. It exhales, when breathed 

 upon, an earthy smell ; is partly soluble in nitric acid, and by cal- 

 cination forms a very strong lime. The author considers it as 

 nearly the same with the calp of Ireland, described by Kirwan, 

 and analyzed by the Hon. Mr. Knox. 



Clay marl, with chlorite (marne chloritee) is placed above the 

 limestones, and from the variety of its characters, and of the 

 containing fossils, appears to have been formed at different 

 epochs : the most ancient is of an olive-green colour ; is mixed 

 with grey hmestone and chlorite ; and is distinguished by the 

 great abundance of its fossils, which are altogether different 

 from those contained in the other varieties of marl. 



The marl (argile calcifere), which succeeds the last mentioned 

 variety, is considered by the author as similar to that which 

 extends from Piedmont to the Appennines ; and from thence, 

 without interruption, to Abruzzo and Puglio ; and which in the 

 Maritime Alps, obviously lies over the limestone, and descends 

 from north to south, to form the chain of hills extending from 

 Montcao to the sea. It contains shells in great abundance and 

 variety, some having little or no resemblance to species at present 

 known ; while the types of others are found on the adjoining 

 sea. Many of the more recent species resemble those of Grig- 

 non, and appear to have been deposited at the same era. The 

 author describes several depots of such shells in the vicinity of 

 Nice, and enumerates the species which they respectively con- 

 tain, amounting to more than 200. 



The pebbles (galets) mixed with, or incumbent on, the marl 

 beds, form an extensive deposit, in layers, which generally range 

 from north to south, and are inclined at a small angle with the 

 horizon. The pebbles are composed of several kinds of lime- 

 stone and sandstones, with petrifactions, quartz, greywacke, 

 and various primitive rocks. Another class of substances, 

 or compounds, comparatively recent, but still of prior forma- 

 tion to the latest catastrophe produced by the sea, consists of 

 marble, breccia, puddingstone, sand, and cla}''. 



The marble, to which the title of Mediterranean has been 

 given, from the great number of Mediterranean shells which it 

 contains, is a very hard and compact calcareous breccia, either 

 white or coloured. It contains the remains of various moUuscee 



