id3 



it wholly and cut out from beneath it the earlier 

 Devonian stage represented by the rocks of Cape Barre 

 and the wharf-foot. This cut-off mass of Devonian 

 extending along the face of the Murailles has itself been 

 faulted across, as indicated. 



The beach depressions both north and south are 

 undoubted displacement areas, the first being the interval 

 between the Devonian of the Murailles and the Silurian 

 of Mt. Joli (North Beach); the second or broad South 

 Beach being the area of general breaking down of the great 

 arch. 



The displacements which took place at a later date than 

 those mentioned have visibly affected only the Bonaventure 

 conglomerate. These may be thus enumerated: (i) The 

 seaward scarp of Mt. Ste. Anne. Bonaventure island 

 seems to be the downthrown mass from this displacement, 

 the "Robin reefs" lying off the South Beach remnants of 

 the same mass; (2) The strata of Bonaventure island 

 dip slightly to the S.W. and the sheer cliffs of the northeast 

 front are a fault face. At the foot of these cliffs the bottom 

 drops immediately to 30 fathoms; (3) The Grand Coupe 

 at the north; (4) The Amphitheatre at the back of Mt. 

 Ste. Anne. 



Relative Thickness of the Older Palaeozoics at Perce. 



Perce beds in Perce Rock 250-300 

 feet but probably rising in Les 



Devonian I Murailles to 500 ft. (153 m.) 



Cape Barre Beds 100 ft. (33 m.) 



Siluro- [Mt. Joli massive 1 , 100 ft. (339 m.) 



Ordovician \Cap-au-Canon massive 600 ft. (200 m.) 



2,300 ft. (725 m.; 



The thickness of the strata at Cap Blanc which are 

 doubtless a repetition of part of the foregoing beds, is 

 800-1000 feet (303 m.). The estimated thickness then ol 

 the pre-Bonaventure beds at Perce [Lower Devonian- 

 Ordovician (Cambrian?)] is about 2,000 feet (606 m.), 

 without making allowance for loss by faulting. 



