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3, 4 an d 5- Clinton Formation. — The recognition of 

 the Rochester shale as a stratigraphic unit compels the 

 adoption of another name for the strata between the shale 

 and the underlying Medina sandstone. These strata are 

 .the equivalent of those in the Niagara section referred 

 to the Clinton, and the fossils show that they are closely 

 related in time to the Rochester. The Pentamerus bed 

 at the base of the formation contains the same form of 

 P. oblongus seen in the Clinton of Rochester, New York. 

 Few fossils are to be obtained except at the top, in the 

 heavy 4-foot bed (1 -2 m.), and at the base, in the Pentam- 

 erus zone. The species are nearly all brachiopods as 

 below: — 



Atrypa reticularis (Linn) 



Camarotoechia neglecta {Hall) 



Leptaena rhomboidalis {Wilckens) 



Orthis flabellites Foerste 



Pentamerus oblongus Sowerby 



Spirifer radiatus Sowerby 



Stricklandinia canadensis Billings 



Whitfieldella cf. cylindrica Hall 



Whitfieldella intermedia Hall 



Whitfieldella nitida Hall 



Whitfieldella nitida oblata Hall 



Dawsonoceras annulatum americanum (Foord) 



Platyceras sp. 



6 and 7. Medina formation. — The Upper Medina 

 may be best seen on the west side of the ravine of Forty 

 Mile creek. The grey band lies almost immediately 

 below the Pentamerus zone and presents excellent examples 

 of Daedalus {Arthrophycus) archimedes Ringueberg. Splen- 

 did examples of Arthrophycus alleghaniensis Harlan, may 

 be obtained on the under side of the sandstone slabs. 

 The typical Medina fossil, Lingula cuneata Conrad, 

 occurs in the lower part of the formation. 



8, 9 and 10. Cataract formation. — The Cataract 

 formation was first officially defined by Professor Charles 

 Schuchert of Yale University at the 1912 meeting of the 

 Geological Society of America. The reading of Professor 

 Schuchert's paper evoked considerable discussion. Dr. 

 E. O. Ulrich being strongly of the opinion that the formation 

 should be included in the Medina or at least in the " Med- 

 inian." It is to be understood therefore that all American 



