350 Dr. Du Riche Preller—Crystalline Rocks, N. Piémont. 
eclogitic gneiss formation in the Sesia Valley and east of the same, 
which has its equivalent in the Kinzig Valley of the Black Forest, 
where it was first recognized and so named by Fischer as early as 
1868. Another equivalent formation is that of the hilly area near 
Monteleone, bordering on the Mediterranean in Calabria.! In all the 
three cases, the rock, greenish brown in colour, gneissic in aspect and 
structure, but more fine-grained, micaceous, and less quartzose than 
primitive gneiss, is often granitoid, and, besides triclinic felspar and 
quartz, contains garnet, omphacite, biotite, sillimanite, and graphite 
as associated minerals. 
From Lanzo to Val Sesia, the sedimentary crystalline formation 
concomitant with the Sesia gneiss is that of eclogitic mica-schists, 
viz. with garnet, omphacite, and blue glaucophane, corresponding to 
those of the Aosta Valley. With the mica-schists and occasional 
minute gneiss intercalations are associated dark-greenish, sericitic, 
calcareous, and quartziferous Permian schists. Both are overlain here 
and there by isolated masses or patches of Lower Triassic, more or 
less crystalline and dark dolomitic limestone, the remnants of a much 
more extensive formation removed by denudation. In the mica-schist 
formation are intercalated— 
(1) he continuous belt of biotitic and amphibolic diorite which 
covers 50 by 5 to 10 kilometres in length and width, and is flanked 
on its southern margin by granite, and on its northern margin by 
minor belts of peridotite, serpentine, and biotitic and pyroxenic 
porphyrite. 
(2) Isolated masses of gabbro, peridotite and lherzolite, granite, 
syenite, and porphyry. 
The coarse-grained gabbro and the peridotitic masses together with 
those of granite and syenite, associated with minute gneiss and mica- 
schist, are prevalent more especially in the hills between Lanzo and 
Ivrea, where a number of interesting, mostly quarried exposures 
occur at Balangero, Corio, Levone, Rivara, Cuorgné, Belmonte, 
Locana, Vidracco, Castellamonte, Baldiserro, Muriaglio, Lessolo, and 
Traversella, in and between the Malone, Oreo, and Chiusella Valleys 
at levels from 400 to 800 metres altitude. Extensive masses of 
granite and syenite also crop out north of Biella in the Cervo Valley, 
while east of Biella to Val Nesia and Lake Orta runs, parallel to the 
diorite belt, a continuous belt of grey and reddish granite 2 to4 kilo- 
metres in width, flanked on the south by a large lenticular mass of 
red porphyry which extends to Borgosesia in the lower Sesia Valley 
and thence to Lake Maggiore. 
1 R. Ugolini, ‘‘ Kinzigite di Monteleone, Calabria’’: Atti Soc. toscana 
Pisa, 1911, p. 55 et seq. 
2 'The eclogitic mica-schist formation with pietre verdi has revealed a con- 
siderable variety of jadeitic and jadeitoid rocks which S. Franchi, V. Novarese, 
and A. Stella discovered both in nodules and blocks in situ and as pebbles in 
the alluyia of rivers in various parts of the Piémontese Alps. -These eclogitic 
and chlorito-melanitic rocks correspond with the Neolithic implements of 
Piémont, thus proving the latter to be, not exotic, but indigenous. ‘‘ Nuovi 
Giacimenti roccie giadetiche ’’: Boll. R. Com. geol., 1900, p. 119; Boll. Soc. 
geol. ital., 1903, pp. 130, 135, 141. 
