312 Dr. M. M. OgiMe Gordon — Mon%oni and Upper Fassa. 



east and west of it ; the cross-fault limiting it against the Allochet 

 ridge is directed N.N.W. - S.S.E., but the cross-fault limiting it 

 against the Fuchiade segment on the east is directed N.N.E.-S.S.W. 

 Hence the leading strike-curve of the Campagnazza is convex to the 

 north. 



The diagonal fault-dykes continue their course northward and 

 cut the Costabella range into similar cross-slices. In the Costabella 

 range the fault-dykes are again continuous with sills which follow 

 the strike, penetrating the strata at various horizons. Two leading 

 sills are fault-sills, — the lower is injected at the horizon of Mendola 

 limestone, the higher is included in a complex shear-zone of Cassian 

 and Schlern limestone horizons. The latter has previously been 

 regarded as the direct continuation of the east- west fault, but it is 

 only one of several branches from the east-west fault, diverging 

 E.N.E. from the Lago di Selle plateau. 



The whole rock succession in the Campagnazza and Costabella 

 has undergone vertical cross-cleavage according to a north-east and 

 south-west (N. 40° E.) strike, and inclined cross-cleavage along 

 a N.W.-S.E. direction with the dip-cleavage planes inclined south- 

 east at an average angle of 35°-4:0°. The intrusions of porphyrite 

 ascend chiefly in the planes of strike-cleavage, and the sills occupy 

 irrespectively the north-dipping bedding-planes and the inclined 

 cleavage-planes with south-east dip. I have incontestible proofs 

 (1) that injections run continuously into the Asta planes and the 

 planes of cross-cleavage ; (2) that the cross-cleavage strike and dip 

 system has disjointed and deformed the Asta strike and dip system ; 

 and I therefore conclude that the leading porphyrite sills and dykes 

 in this area were coeval with the superposition of the cross-cleavage 

 system. In previous papers I have called the cross-cleavage system 

 the ' Judicarian ' system, and referred it to the Miocene geological 

 epoch, treating it as a more advanced phase in the protracted history 

 of superposed movements than that which gave origin to the E.N.E. 

 and W.N.W. strikes. The ' Judicarian ' and ' Asta ' systems of 

 strike have orthogonal correlation with one another, the N.N.E. 

 ' Judicarian ' strike being rectangular to the W.N.W. ' Asta ' strike, 

 and the N.N.W. ' Judicarian ' strike being rectangular to the 

 E.N.E. ' Asta ' strike. Thus cross-cleavage was superinduced upon 

 the ' Asta ' strike - system, but the differences in the detailed 

 stratigraphy of the cross-segments in the Campagnazza show that 

 both systems were acting simultaneously, the orthogonal stresses 

 being associated with the superposition of the N.N.E.-S.S.W. or 

 ' Judicarian ' strike upon the fundamental east- west ' Alpine ' strike. 



The Cross-Cleavage op Monzoni. 



The ' Asta ' injection of monzonite apparently engulfed the strati- 

 fied rocks of the Permian and Werfen horizons, and as it consolidated 

 did so in conformity with the actual strike and dip of the bedding- 

 planes above, around, and amidst them. The rock-magma, owing 

 to the action of the local pressure-strains, consolidated as a series 

 of gneissose zones, and these original segregation zones have the 



