CATARACT FAUNA 281 



cosa, Phylloporina dngulata, Hehertella fausta, Atrypa n. sp. (a miilti- 

 striate and large form of A. marginalis type), and Ccelospira planocon- 

 vexa. 



Basal Cataract or Whirlpool sandstone (Grrabau).^ — This coarse, cross- 

 bedded, white, red, or mottled sandstone occurs at the base of the Cataract 

 all the way from Lockport, ^ew York, to near Collingwood, Ontario, a 

 distance along the outcrops of about 150 miles. The thickness varies be- 

 tween 22 feet and 6 feet, with the maximum in the southeast. Farther 

 northwest the limestones make the base of the Cataract formatioUj and 

 therefore one of these two basal members rests with sharp distinction and 

 disconformity on either the Queenston or Richmondian of the Orqlovicic. 



The Whirlpool is practically barren of fossils, though at the very top a 

 few forms may be had, chiefly worm burrows and more rarely Modio- 

 lopsis (?) orthonota. 



THE CATARACT FAUNA 



HalF described from or identified at Flamborough Head, near Dundas, 

 9 species, all erroneously determined as from the Clinton. Logan and 

 Billings^ list a larger number of forms, also from the "Clinton,^' all of 

 which are in the Cataract formation. Nicholson^ has a list of 29 species 

 that are also said to be from the Clinton, but in reality are from the 

 Cataract, and Parks^*^ lists at least 31 forms. A part of Grabau's^^ 

 Medina fauna likewise belongs here. 



The followbig list combines all previous lists, contains those additional 

 species identified by the writer, and eliminates the forms now known not 

 to occur in this fauna. The symbols used are as follows : * = restricted 

 to Cataract, X = of no stratigraphic value, + = also in higher forma- 

 tions, -| — 1- = affinity upward, m = also in Medina, and b = also in 

 Brassfield. 



FucoiDs: 



XBythotrephis gracilis intermedia and B. gracilis erassa Hall. Common 

 at various horizons in the two upper members. Identified by Nichol- 

 son. 

 Burrows : 



mXScolithus verticalis Hall. Dundas and elsewhere in the Whirlpool. 

 At Stony Creek, in the Medina. Originally described from the Medina 

 of New York. 



"Jour. Geol., vol. 17, 1909, p. 238. 



7 Pal. N. Y., vol. li, 1852, pp. 41-51. 



8 Geol. Canada, 1863, pp. 313-321. 



8 Kept. Pal. Prov. Ontario, pt. 2, 1875, pp. 40-49. 



10 Guide Book No. 5, Inter. Geol. Congr., 1913, pp. 10-12. 



^Loc. cit, 



