NIAGARAN (aNTICOSTIAN) SERIES 707 



typical Eichmondian species, l)iit rather Siliiric forms. On the other 

 side^ the Becsie Eiver deposits often abound in fossils, and yet the species 

 are few in number and all are Silnric in aspect. The writers realize that 

 such differences in the faunas are most readily explained by assuming a 

 time break between the Ellis Bay and the Becsie Eiver formations and 

 that the latter rests disconformably on the former. At the time these 

 field studies were made^ no physical evidence of an hiatus was observed, 

 but it may be that such actually exists. Such contacts are very easily 

 passed over, and especially when one accepts the conclusion of Billings 

 and Eichardson that the entire Anticosti strata represent an unbroken 

 series beginning in the early Eichmondian and continuing well up into 

 the Siluric. On the other hand, the appearance of the yellowish gray 

 to brown brittle limestone characterizing this formation, and occurring 

 at various levels from A to E, is always accompanied by a sparse fauna. 

 At the top of Junction Cliff this type of limestone is marked by Atrypa 

 marginalis almost alone, and such may be in part the explanation for the 

 faunal change at the base of the Becsie Eiver formation. 



The- nearest approach to the faunas of zones D^ to D^ are those of the 

 sandy strata referred to the Clinton and occurring at Dundas, Flambor- 

 ough Head, Thorold and Hamilton, Ontario, and in the lower thin- 

 bedded arenaceous shales of the upper Medina of the Niagara Eiver gorge 

 at Evans Gully. At the latter place these strata are always regarded as 

 of the upper Medina, but in a distance less than 30 miles to the north- 

 west the identical horizons are referred by Logan^^ to the Clinton. The 

 thickest section is near Dundas and measures about 100 feet in depth, a 

 development in harmony with the upper Medina of the Niagara Eiver 

 gorge. In the lower 10 feet just above the "gray band" occur, near 

 Dundas, Zaphrentis stokesi, Helopora fragilis, Pachydictya crassa, Phce- 

 nopora ensiformis, Rhinopora verrucosa, Leptcena rhomb oidalis^ Scliu- 

 cliertella pecten, DalmaneJJa elegantula, Rliynclionella (?) neglecta, Ano- 

 plotheca planoconvexa, Whitfieldella naviformis, Atrypa reticularis, 

 Spirifer radiatus, Modiolopsis ortlionota, Murchisonia ( ?) subulata, and 

 Encrinurus punctatus. In higher strata occur the same species, espe- 

 cially the tjrpical Medina forms, but A. planoconvexa is restricted to the 

 lowest beds. 



At Hamilton, Ontario, the senior author has gathered the identical 

 fauna in the so-called Clinton beds, here having Arthrophycus liarlani, 

 and again, but in fewer species, in Evans Gully, near Niagara Falls^ in a 

 zone 25 feet thick above the heavy bedded sandstone making here the 



" Logan : Geology of Canada, 1863, pp. 312-315. 



