BAYFIELD ON THE TRANSITION ROCKS OF CANADA, ETC. 457 



4. Leptaena sericea. 7. Atrypa reticularis ; (syn. 



5. Orthoceras. A. affinis & A. prisca). 



6. Favosites gothlandica. 8. Turbo. 



9. Pentamerus oblongus. 



These, although doubtless far from comprising all that may be 

 found, will be sufficient to establish the Silurian character of the 

 limestone of these islands, and to show the general resemblance of 

 the fauna to that which is indicated by the organic remains of 

 similar formations occupying an analogous position in Europe. 



From the Mingan Islands to the Strait of Belle Isle, the coast of 

 Labrador consists exclusively of primary rocks, but on the east side 

 of Bras d'or Harbour we meet with transition sandstone, which at 

 one point appears to pass distinctly into gneiss. The sandstone 

 extends about thirty miles along the northern side of the Strait of 

 Belle Isle, from Bras d'or to the eastward, and forms table-lands 

 400 or 500 feet high, with cliffs towards the sea, and terraces 

 ascending one within the other to considerable distances inland. 

 These seem due to aqueous denudation, and, like the inland cliffs 

 and flower-pot columns of the Mingan Islands, may mark, although 

 less distinctly, successive periods during the emergence of the 

 sandstone from the sea. This sandstone occurs in nearly hori- 

 zontal strata, dipping, if at all, very slightly to the southward, and 

 resting on granite. On the eastern point of Fortean Bay, a red 

 and white limestone * underlies the sandstone, and contains Cya- 

 thophyllum ; which fact, together with its position, immediately 

 reposing on granite, affords the only data from which to infer the 

 relative age of this formation. 



The opposite, or Newfoundland side of the strait is of lime- 

 stone ; containing, at Cape Norman, Orthoceras duplex, Orthoceras 

 allied to O. annulatus, Euomphalus affinis, E. gualteriatus, and 

 Clymenia ? or Lituites. I observed this limestone, which is in 

 nearly horizontal strata, as far to the southward along the west 

 coast of Newfoundland as Port Saunders, and it probably extends 

 still further in that direction. It is then succeeded by sandstones, 

 and perhaps by other rocks in ascending order to the coal, which 

 is reported to occur in St. George's Bay. 



At Chatian Bay, and also at Table Point, opposite Belle Isle, 

 we met with columnar basalt f capping granitic hills, at an eleva- 

 tion of about 200 feet above the sea. The basalt is in vertical 

 prisms 25 or 30 feet high, having from five to eight sides. It is 

 black, ferruginous, magnetic, and contains crystals of olivine. It 

 rests, at Table Point, upon a conglomerate of rounded pebbles of 

 quartz and felspar, with oxide of iron and silvery mica, the whole 

 so changed by the contact that, in some hand specimens, we might 

 almost take it for granite. It has also acquired an irregularly 

 prismatic structure, large columnar masses of it breaking away 



* It is worthy of remark that a somewhat similar limestone, but destitute of 

 organic remains, was observed by Dr. Bigsby underlying and alternating with 

 sandstone at Thunder Cape on Lake Superior. 



f Literary and Historical Society of Quebec, vol. i. p. 7J. 



