CHAPTER XII. 



Geological monuments of the older Pliocene period Subapennine formations 

 Opinions of Brocchi Different groups termed by him Subapennine are not 

 all of the same age Mineral composition of the Subapennine formations 

 Marls Yellow sand and gravel Subapennine beds how formed Illustra- 

 tion derived from the Upper Val d'Arno Organic remains of Subapennine 

 hills Older Pliocene strata at the base of the Maritime Alps Genoa Savona 

 Albenga Nice Conglomerate of Valley of Magnan Its origin Tertiary 

 strata at the eastern extremity of the Pyrenees. 



OLDER PLIOCENE FORMATIONS. 



WE must now carry back our retrospect one step farther, 

 and treat of the monuments of the era immediately antecedent 

 to that last considered. We defined in the fifth chapter *, the 

 zoological characters by which the strata of the older Pliocene 

 period may be distinguished, and we shall now proceed at once 

 to describe some of the principal groups which answer to those 

 characters. 



Subapennine strata. The Apennines, it is well known, are 

 composed chiefly of secondary rocks, forming a chain which 

 branches off from the Ligurian Alps and passes down the 

 middle of the Italian peninsula. At the foot of these moun- 

 tains, on the side both of the Adriatic and the Mediterranean, 

 are found a series of tertiary strata, which form, for the most 

 part, a line of low hills occupying the^space between the older 

 chain and the sea. Brocchi, the first Italian geologist who 

 described this newer group in detail, gave it the name of the 

 Subapennines, and he classed all the tertiary strata of Italy, 

 from Piedmont to Calabria, as parts of the same system. 

 Certain mineral characters, he observed, were common to the 

 whole, for the strata consist generally of lightbrown or blue marl, 

 covered by yellow calcareous sand and gravel. There are also, 



* Above, p. 54. 



