310 Dr. Dw Riche Preller—Crystalline Rocks, N. Piémont. 
outer belt, a more or less continuous fringe of calc-schist and pietre 
verdi extends all round the periphery of the massif, stretching from 
Monte Bellavarda in the Stura Grande Valley north to the Orco and 
Cogne Valleys and thence north-east to the Champorcher and Clavalité 
Valleys, where it forms a separate, considerable area. Throughout 
this belt, the pietre verdi present all the varieties of those of the 
Lanzo valleys, including more especially glaucophanic amphibolites 
and omphacitic eclogite. Along its eastern margin this cale-schist 
and pietre verdi belt is contiguous to the mica-schist horizon with 
large intercalations of minute and tabular gneiss conspicuous by its 
green mica; in the Lanzo valleys this gneiss is quarried near 
Pessinetto, between Lanzo and Ceres. The eastern spurs of the 
mica-schist area form part of the Lanzo-Ivrea belt to be described 
later. 
II. Tae Dora Batrea ARga. 
The Val d’Aosta comprises in its middle course important pietre 
verdi groups, both on the right and left of the Dora Baltea. On the 
right the most remarkable areas are those of Punta Grivola, Monte 
Emilius, and Monte Rafré, and on the left the Mont Mary group.! 
1. The Grivola Area (Figs. 1 and 2).—About 10 kilometres north 
of Gran Paradiso, but outside the gneiss massif, and in the surrounding 
calc-schist formation, rises the Grivola peak (3,969 m.), which in its 
pyramidal grandeur vies with Matterhorn and Monte Viso. Its 
position is rendered the more commanding by the scooped out valleys 
of the Cogne on its eastern and northern, and of the Sayaranche on 
its western flank, both of which torrents, as already mentioned, rise 
in the Paradiso massif and discharge into the Dora Baltea near 
Villeneuve (670m.). The ridge which rises from Villeneuve? 
between the two valleys to the crest of Grivola and Grivoletta 
(3,526 m.) in a horizontal distance of 12 kilometres presents, in an 
interesting natural section, a complete sequence of rock formations 
which, in ascending order, may be summarized as follows :— 
Superficial 
width. Altitude. 
Villeneuve. Lias and Trias: Fossiliferous limestone, ordinary ) km. m. 
facies. ; : j Bille 700 
Cale-schist and crystalline lime- 
stone . Y ; : é 2,000 
Becca Piana. Permo-Carboniferous: Sericitic, graphitic, gneissi- 
form, and psammitic schist Z ‘ : . 1 2,800 
Gran Nomenon. Sphenicdiorite . f : : : . 4 3,500 
Sericitic, graphitic, gneissiform, and psammitic 
schist ; : : - é : . 1 3,500 
Grivola. Lias and Trias: Crystalline limestone, cale-schist, and 
prasinites 5 : ‘ : RO BEAN 
12 3,200 
1 The whole region between the Aosta and Orco Valleys, including the 
Paradiso massif, is, perhaps more than any other part of the Piémontese Alps, 
rendered conveniently accessible by the numerous mule paths of the Royal 
shooting preserves. An excellent topographical map of the Val d’Aosta, 
Lanzo, and Ivrea region, 1 : 250,000, is that by V. Novarese in Boll. R. Com. 
geol., 1913-14, p. 244, ‘‘ Il Quarternario Valle d’ Aosta e Valli Canavesi.’’ 
2 Villeneuve is one of the localities where S. Franchi found fossils in 
Triassic limestone intercalated in cale-schists. ‘‘Terreni secondarie facies 
Piémontese’’: Boll. R. Com. geol., 1909, p. 526 et seq. 
