Professor Hoffmann on the Geology of Massa Carrara. 117 



basin-shaped widening of the valley lies Carrara. The highest 

 summits of this mountain chain, the Pizzo cTUccelb and the 

 Pallia della brace, are not quite 5800 Parisian feet above the 

 level of the sea. On the side next the sea, talc-slate and mica, 

 slate are the oldest rocks which make their appearance ; they 

 dip regularly to the south-west, and in their lower beds, or in 

 the inner higher parts of the bottoms of tlie valleys of the Sena 

 and Frigido, pass into a distinct gneiss. Limestone masses oc- 

 cur very frequently throughout the whole extent of the slaty 

 rocks, and are particularly numerous and extensive in Senavezza. 

 Most of them are interstratified with the general arrangement 

 of the beds, and traversed by subordinate layers of slate which 

 run in a similar direction to the general stratification. They.alj 

 most all consist of a grey or nearly white crystalline-granular 

 limestone, veined or striped by lighter or darker colours, and 

 which is generally known by the name of Bardiglio. Besides these 

 regular interstratified hmestone masses, others appear in the slate 

 having less regularity, and greater variety of structure. The 

 largest of these is that which, completely surrounded by slate, 

 forms the Monte Altissimo on the north side of Senavezza, rises 

 to the height of upwards of 5000 feet above the level of the sea, 

 and whose south side forms towards the valley of the Sena a 

 rocky precipice 3000 feet in height. Here the limestone, jli 

 placed, like a long, obtusely acuminated wedge, between thfe 

 masses of slate. The gneiss turns suddenly round before this 

 limestone mass, under a very high inclination to the north-ef^sti 

 while the latter dips to the south-west ; on the bounding side of 

 the valley the junction of the two rocks is displayed in a preci- 

 pice of at least 1000 feet in height, and the bending of the gneiss 

 round the included limestone is distinctly visible. On the oppo- 

 site declivity of the AUissimo, and following the limestone are 

 the strata of slate, which are nearly perpendicular, or dip tp^ 

 wards the limestone on the south-west. Still more remarkable 

 than this arrangement is the structure of the great limestone mass 

 of the Altissimo. Where the slate appears in contact with the lime? 

 stone, the latter is by no means a perfectly formed marble, but 

 is an impure ash-grey, fine granular, almost compact limestone, 

 which one would declare to be secondary lim^stone^ if he.did 



