272 DE. J. W. GREGORY ON THE WALDENS1AN [May 1 894, 



With the exception of No. 5, these six divisions may be arranged 

 into two groups ; the first includes Nos. 2, 3, 4, and 6, the axes or 

 directions of which have a general north or north-westerly to south 

 or south-easterly range ; the second includes the transverse fold of 

 the Northern Cottians. The detailed work of Kilian and Haug 1 has 

 shown that the dislocations of the Subalpine chains to the west may 

 also he grouped into approximately meridional and transverse series. 



It is tempting to try to correlate these with the dislocations of the 

 Cottians, but this cannot be done, except in a very general way. 

 Kilian points out that in the mountains of Lure the north-and-south 

 series are pre-Miocene, and the east-and-west series post-Upper 

 Miocene. Similarly in the Gap-Digne area the N.W.-and-S.E. 

 folds are pre-Aquitanian (Upper Oligocene) and possibly Lower 

 Eocene, whereas the east-and-west set are mostly Helvetian (Middle 

 Miocene), though some are pre-Aquitanian. The same probably 

 holds in the Cottians : the east-and-west fold of the Northern 

 Cottians is apparently connected with the Paradiso intrusion, and 

 is probably Miocene, certainly pre-Pliocene. The Pliocene beds 

 of the Villafranchian stage on the eastern flank have been raised 

 over 1500 feet by a movement which closed that period. 2 As, 

 however, the Paradiso gneiss was exposed before this, a fact proved 

 by the evidence of the Miocene conglomerates, this Pliocene move- 

 ment must have followed along the old line. The crushing of the 

 contact-rock between the gneiss and the schists may have been 

 caused by such later movements. 



The absence of fossiliferous Tertiary beds in the Cottians pre- 

 vents any such definite determination of the succession of the 

 movements as is possible in the Subalpine mountains of Dauphine. 

 Nevertheless a rough order may be safely established for the re- 

 maining five sets of dislocations. No. 5 is probably Upper Mesozoic, 3 

 owing to the agreement of its rocks with those of the Mont Genevre 

 variolitic series ; typical specimens of variolite derived from this 

 mass occur in the bed of the Sangonetto above Pale. Nos. 3 and 4 

 are both later than the Cretaceous, some beds of which are included 

 in the limestone series of Chaberton. No. 2 is still later, as it has 

 cut through the overthrust limestones both at the Roc del Boucher 

 and at Chaberton. These three sets, Nos. 2, 3, aod 4, are probably 

 more closely allied than the others ; they are the result of enormous 

 lateral compression and strain, and the secondary foliation so fre- 

 quent in the schists of the district is probably due to them. The 



1 Haug, op. supra cit. pp. 184-187. 



2 Sacco, ' II Cono di dejezione della Stura di Lanzo,' Boll. Soc. geol. Ital. 

 vol. vii. (1888) p. 160; see also Gastaldi. Mem. descriz. Carta geol. Italia, 

 vol. ii. (1874) pi. ii. 



3 The latter basic series is accepted as Upper Mesozoic (probably Cenoma- 

 nien) on the authority of Prof. Sacco's demonstration that the Ligurian beds 

 containing the serpentines of Liguria are Cretaceous and not Eocene, ' L'Age 

 des Formations ophiolitiques recentes,' Bull. Soc. Beige Geol. Pal. vol. v. (1892) 

 Mem. pp. 60-95. 



