278 C. SCHUCHERT MEDINA AND CATARACT FORMATIONS 



Page 



Thorold, Ontario, section 310 



Grimsby, Ontario, section 310 



Stony Creek, Ontario, section 311 



Hamilton, Ontario, section 313 



Dundas, Ontario, section 315 



Limehouse, Ontario, section 31G 



Glenwilliam, Ontario, section 317 



Cataract, Ontario, section 317 



Collingwood, Ontario, section 318 



Owen Sound, Ontario, section 319 



Cabots Head, Bruce Peninsula, Ontario, section 319 



Manitowaning, Manitoulin Island, Ontario, section 320 



Introduction 



This contribution to stratigrapli}- redefines the Medina formation and 

 describes the character of its strata and fauna in the typical area in the 

 State of New York, The new Cataract formation of Ontario is also de- 

 scribed in detail and its fauna listed. Some of the most characteristic 

 species of the latter formation were formerly ascribed to the Clinton, 

 but it is here shown that the Cataract is equivalent to the Medina — the 

 typical Medina as seen at Medina, New York. Finally, these two forma- 

 tions are compared with the Brassfield of Ohio, which has also been corre- 

 lated with the Clinton, but is now seen to be of a])out the same geologic 

 time as the Cataract and the Medina. 



The following account of the Cataract, Medina, and Brassfield is 

 divided into two parts. Part I contains a general discussion of the for- 

 mations, their faunas, and their interrelations. In the second part is 

 given a historical review of the Medina and the status of the various 

 formation names, followed by a detailed description of sixteen sections 

 extending from Rochester, New York, to the Manitoulin Islands, a dis- 

 tance of 340 miles, and taken at the places in which the Medina and 

 Cataract formations are best exposed. Hence the detailed evidence for 

 the nomenclature and stratigraphy discussed in Part I will be found in 

 Part II. 



Part I 



THE CATARACT FORMATION 



General discussion of the formation. — The writer became acquainted 

 with this formation at Hamilton and Orimsby, Ontario, in September, 

 1895, under the guidance of that grand old naturalist. Col. Charles Coote 

 Grant. The formation was then known as the Clinton formation, due 



