92 



Diphyphyllum cf. huronicum (Rominger). 

 Diphyphyllum multicaule (Hall). 

 Favosites aspera d'Orbigny. 

 Halysites catenulatus microporus (Whitfield). 

 Zaphrentis bilateralis (Hall). 

 Apiocystites tecumseth (Billings). 

 Pachydictya crassa (Hall). 

 Anoplotheca planoconvexa (Hall). 

 Atrypa cf. marginalis (Dalman). 

 Camarotoechia neglecta (Hall). 

 Orthis flabellites Foerste. 

 Platystrophia biforata (Schlotheim) . 

 Rhipidomella hybrida (Sowerby). 

 Schuchertella subplana (Conrad). 

 Whitfieldella nitida (Hall). 

 Cyclonema cancellatum Hall. 

 Orthoceras sp. 



This formation is found to be the same as the Cataract 

 at Cataract, Hamilton, and other places along the Niagara 

 cuesta. It was formerly confused with the Clinton, but 

 it undoubtedly lies below the typical Medina sandstone 

 with Arthrophycus. On this account it has been erected 

 into a new formation and includes the Whirlpool sandstone. 

 (See guide books to Excursions B3 and B4.) 



The shale of the Cataract formation has a clayey 

 texture and is generally of an iron red colour. Some green 

 discoloration occurs near the top due to leaching and 

 consequent reduction of the iron bearing minerals, 

 fossils have been found in the shale. 



Lockport (Niagara) formation. — The Lockport for- 

 mation consists of thin-bedded to thick-bedded, massive 

 dolomites. At the base, directly above the red Cataract 

 shale, the dolomite is thin-bedded and arenaceous, con- 

 taining numerous Pentamerus oblongns. 



A sparing coral fauna starts about 80 feet (24-4 m) 

 above the base of the formation and reaches its maximum 

 about 100 feet (30 m.) up. The last 30 feet (9-1 m.) 

 of the formation, as occurring in the thickest sections 

 studied, is massive and nearly unfossiliferous. The most 

 characteristic fossils from the Lockport of Manitoulin 

 island are: — 



Arachnophyllum pentagonum (Goldfuss). 

 Arachnophyllum striatum (D'Orbigny). 



