120 Professor Hoffmann on the Geology of Massa Carrara, 



confused and altered it. Out of the slate formation of which 

 we have spoken, there is only one limestone formation which 

 presents itself in any considerable quantity in the Apuanian Alp. 

 It rises to the height of 5728 feet above the level of the sea, in 

 the rocky cone of Pania della Croce, and in some places forms 

 walls which are frightfully perpendicular. On the great scale, 

 and on the whole, this limestone formation occurs always above 

 the slate. It is only along the declivity of the Tamhura ch^n, 

 which is directed to the south-west, that this position is reversed. 

 There the slate reposes regularly on the limestone, and one can- 

 not believe any thing else than that this steep elevated chain has 

 been overturned in its whole extent at the south-western edge. 

 The relations of the internal structure, and the occurrence of 

 the characteristic alterations of this limestone, render it difficult 

 to convey a distinct idea of it. On this account the author se- 

 lected the description of distinctly displayed sections, such as 

 those which occur in the mountain group of Carrara. Among 

 these there is no one so perfect and varied as that at the north- 

 west corner of the group, in the direction from Castelpoggio to 

 Tenerano. Castelpoggio is placed on the lowest beds of the 

 Macigno formation, which consists of red compact limestones 

 penetrated by oxide of iron, alternating with red and grey slaty 

 marls, which not unfrequently resemble old clay-slate. Here, 

 as in other places, the Macigno formation is traversed by veins 

 of quartz and calcareous spar, and very frequently blood-red 

 jasper and hornstone occur in nodules or thin layers. The dip 

 is to the south-west, under an angle of 48°. Under the Macig- 

 no commences next the rauchwacTce, which has a blackish-blue 

 colour, and is coarsely vesicular. Sometimes this rock loses its 

 porosity, and becomes a marble of an inferior description, or it 

 becomes a regularly stratified limestone, which not unfrequently 

 alternates with slaty marls, that have completely the appearance 

 of the layers of calcareous clay-slate which so frequently occur 

 with the old limestone in the German transition series. At the 

 junctions of the layers of limestone petrifactions occur, viz. small 

 species of Ostrea, Pecten, Cardium, Terebratula, and many 

 traces of corals. In the slates, bodies resembling scales of fishes 

 occur, and with them an Jvicula and a Corhula. Upon this 

 jmesione follows, about 600 feet under the pass, unstratified. 



