310 T. Davidson — On the Geology of Nice. 



naturally dipping in an opposite direction to that of the principal 

 axis ; consequently we see nearly all the lower formations in suc- 

 cession tilted up and set back to back almost continuously against 

 the central axis, but generally in a more or less metamorphic condi- 

 dition at, or near, their point of contact with the unstratified or 

 igneous mass. 



The quartzose derivatives which border the granito-gneissic crys- 

 talline nucleus, are sienites, eurites, porphyries, serpentines, schists, 

 etc ; the Grey wacke and Saliferous schists lie close to these first deri- 

 vatives. The Carboniferous formation follows a parallel direction 

 to that of the great axis of upheaval of the centre of the basin of the 

 Maritime Alps, and forms a band in the shape of a bird's tongue, 

 which, extending from north-east to south-west, denotes the con- 

 tinuity of this formation by Draguignan to the Esterel. This 

 band is margined by different stages both of the lower and 

 middle Jurassic series. Now, as the metamorphic action has 

 affected all the rocks in its immediate contiguity, we find the 

 Liassic stages have, in part, been converted into marble, while 

 the Oolitic, Oxfordian, Coralline, and Portlandian stages are often 

 transformed into Sulphate of lime, forming at the same time 

 minor centres of chemical action, of which the neighbouring 

 parts are frequently converted into Dolomite, and where the 

 magnesian influence has often reduced them into a coarse sand, 

 causing frequent doubt to arise in reference to their age : added to 

 all this, their poverty in fossils deprives us of that which might 

 otherwise have afforded a means of identification. 



The Cretaceous strata attain a thickness nearly equal to that 

 of the Jurassic, and being in close approximation to the posterior 

 portion of the centre of our Alpine basin, have in turn undergone 

 enormous convulsions, — as may be perceived from the almost vertical 

 inclination of the beds and their numerous flexures. These con- 

 tortions and contractions are accompanied by numerous faults, frac- 

 tures, and overthrows in the stratiflcation ; thus causing, at times, 

 considerable uncertainty as to the age of the deposits, or where the 

 line of contact with the lower or upper one commences or terminates. 

 Some of the stages are rich in organic remains. 



The Tertiary deposits, which spread over nearly the whole of our 

 Alpine crests, terminate the Department at its four angles, and the 

 extremities of these outliers are lost beneath the Mediterranean. 

 Others do not extend higher than the middle of the Alpine basin, 

 and the average thickness of the strata nearly equals that of the 

 larger number of the Cretaceous ones. The rocks of this period 

 in the district surrounding Nice have undergone no modification 

 by the action of former chemical influences, but in other portions of 

 the Department certain changes have taken place. The lower and 

 upper Tertiary strata are very rich in fossils, though very much out 

 of shape (see the much esteemed works of Messrs. Deshayes, E. 

 Sismonda, and L. Bellardi, of which the detailed catalogue of the 

 Nummulitic fossils from the ancient county of Nice is sufficiently 

 recent, 1853). 



