C. D. Walcott — Position of the Olenellus Fauna. 375 



In commenting on the table the author (Logan) said : " It 

 thus appears that the lower portion of the series is complete in 

 Newfoundland, and the upper in New York and Central Canada. 

 Divisions 3, 4 and 5 have not yet been recognized in the East- 

 ern continental region. The St. John's group, 1, is represented 

 at St. John, New Brunswick by 3,000 feet of black slates and 

 sandstones, whose fauna, described by Mr. Hartt, was correctly 

 referred by him to Etage C of Barrande's Primordial zone. 

 It there reposes on older schistose rocks, as yet unstudied, but 

 by Messrs. Hartt and Matthew designated as Cambrian. 



"The slates of St. John, New Brunswick, Newfoundland, 

 and the Paradoxides beds of Brain tree, Massachusetts, also 

 probably belong to the same horizon. 



" The Lower Potsdam, 2, is represented by several hundred 

 feet of limestones and sandstones on the Straits of Belle Isle, 

 and on White Bay, Newfoundland, and by the slates of St. 

 Albans and Georgia, Vermont. 



" The Upper Potsdam, 3, is that of Wisconsin and Min- 

 nesota, represented in the typical Potsdam of New York, 

 which is overlaid by the Lower Calciferous, 4, while the Upper 

 Calciferous, 5, is only recognized in the Northern peninsula of 

 Newfoundland."* 



This order of succession was accepted and adopted by Amer- 

 ican geologists while no stratigraphic evidence appeared that 

 negatived it. It was not questioned until the work of the 

 Swedish geologists showed that Olenellus Kjerulji occurred 

 beneath the Paradoxides zone in Sweden ; then it became 

 probable that the American Olenellus fauna was of a similar 

 age and hence older than the Paradoxides fauna. 



Mr. S. W. Ford adopted the classification of Billings and 

 Logan, and argued from the embryonic phases of growth of 

 Olenellus asaphoides that the species showed a genetic relation 

 to Paradoxides and succeeded it in time — a view in which I 

 concurred at a later date.f Mr. Ford held that Olenellus 

 Kjerulji was a true Paradoxides, allied to P. Olandicus% and, 

 on the report of Mr. Matthewg that he had found the species 

 in America, decided that it, O. Kjerulji, belonged to the Me- 

 nevian fauna. 



Mr. G-. F. Matthew has studied the Paradoxides fauna of 

 America with more thoroughness than any other paleontologist 

 and he has concluded from the paleontological evidence that it 

 preceded the Olenellus fauna. || In the introduction of the 



* Bull. U. S. Geol. Survey, No. 30, p. 64, par. 141. 

 \ Bull. U. S. Geol. Survey, No. 30, 1886, p. 166. 

 ± This Journal, III, vol. xxxii, 1886, pp. 473-476. 

 § This Journal, III, vol. xxxi, 1886, p. 472. 

 |[ Canadian Record Sci., vol. iii, 1888, pp. 71-81. 



