CHAZIAN AND MOHAWKIAN SERIES 689 



York Black Eiver is not seen here, and as the lower 65 feet of his Large 

 Island section are now known to belong to the Eomaine series, his thick- 

 ness for the Mingan series reduces to 292 feet, which is still 50 feet 

 greater than the writers' measurements. 



Mingan formation, Zone A-^. — The basal strata of the Mingan series 

 have been seen in contact with the Eomaine formation on Quarry Island, 

 on the east side of Deep Cove of Large Island, on Harbor Island^ and on 

 Parroquet Island. In these places it is a gray to w^hite coarse sandstone 

 or conglomerate of quartz pebbles, and in all observed cases is decidedly 

 cross-bedded. This zone varies in thickness from 18 inches (Quarry 

 Island) to 5 feet (Deep Cove). Therefore there are here the invading 

 shore deposits of the Chazian sea over the then land of Beekmantown 

 dolomites. The fossils here are rolled and broken individuals of Oi^this 

 ignicida and Rhynchotrema (?) orientalis. The basal conglomerate is 

 absent on Parroquet Island and was not observed at Clear Water Point, 

 as the Eomaine series is here directly followed by the shales of the next 

 division. 



Mingan formation. Zone Ag. — The conglomerate zone is followed by a 

 variable series of shales, calcareous sandstones, and limestones having a 

 united thickness varying between 10 and 20 feet. These beds may be 

 known as Mingan Ag zone. On Quarry Island, where the conglomerate 

 is 5 feet thick, there follows dark greenish arenaceous shale with a thick- 

 ness of 7 feet, while that on Large Island is 11 feet thick. On Quarry 

 Island this shale is succeeded by a yellow to light green, fine grained, 

 highly calcareous sandstone between 4 and 5 feet thick, a bed of greenish 

 arenaceous limestone, and finally 20 inches of green arenaceous shale 

 with thin sandstones that locally may change into a brittle greenish lime- 

 stone. 



On the Parroquet Islands, where the basal conglomerate does not occur, 

 the Eomaine series is followed directly by a zone of dark greenish to 

 black, rusty M^eathering shale that is nearly 6 feet thick. Above this is a 

 6-inch zone of white granular limestone (wanting on the north side of 

 the island), followed by more dark greenish carbonaceous shale slightly 

 micaceous, having a thickness of between 6 and 8 feet. In these higher 

 shales there are fragments of Lingula, Conularia, and Serpulites disso- 

 lutus ?. Then follows a greenish white limestone 2 feet thick and a final 

 green shale zone of 10 inches. 



On Phantom Island, east of Quarry Island, above the conglomerate 

 there follows a dark greenish to black shale 6 feet thick, but thinning to 

 less than 3 feet when traced eastward; then 4 feet of calcareous sand- 

 stone, 20 inches of dark shales, and 5 feet of arenaceous limestone that is 



