walcott.] NEWFOUNDLAND. 51 



ides, collected from the upper slate of St. Mary's Bay, Newfoundland, 

 which he described under the name of Paradoxides bennetti, calling 

 attention to its relation to Paradoxides spinosus and P. bohemicus, of 

 Bohemia. 



In 1862', Prof. Jukes, referring to his work in Newfoundland, stated 

 that he included under the upper slate formation the Bell Isle shale 

 and gritstone and variegated slate; and in the lower slate formation the 

 Signal Hill sandstones and St. John's slate. He says he did not find 

 any fossils in them, but that Mr. 0. Bennett subsequently found trilo- 

 bites of the genus Paradoxides (named P. bennetti by Mr. J. W. Salter) 

 in the slates on the west side of St. Mary's Bay. " These slates belong 

 to the group I called the St. John's slate, which is covered conformably 

 by the Signal Hill sandstone. The Variegated slate group, on the other 

 hand, passes up into the Bell Isle shale and gritstone, and near Brigus 

 Harbor, in Conception Bay, may be seen to rest unconformably on the 

 St. John's slate" (as described in 1843). l This is the unconformity 

 now recognized between the Cambrian and Algonkian rocks. 



Eighteen years after Captain Bayfield had reported on the strata of 

 the north side of the straits of Belle Isle, Sir William E. Logan 2 des- 

 cribed the strata resting on the gneiss as red and green sandstones, 231 

 feet thick, overlain by gray, reddish, and greenish limestone. In the lime- 

 stone a number of fossils were found which Mr. Billings identified with 

 those found in the " Bed Sandrock " of Vermont. The formation was re- 

 ferred to the Lower Potsdam by Logan. Fifteen miles across the straits, 

 on the Newfoundland coast, the rocks are apparently of Calciferous age; 

 and he concluded that the Potsdam sandstone zone was buried beneath 

 the waters of the Straits. 3 In the description of the section at Bonne 

 Bay, on the west coast of Newfoundland, 4 it is compared with that at 

 the Straits of Belle Isle; and on x>ages 865-867, the section at Bonne 

 Bay is given in detail. Of this 1,711 feet are, by the contained fossils, 

 referred to the Potsdam group. 



In the report of the Geological Survey of Newfoundland for 1864 5 a 

 summary is given of the then existing view of thesuccession of the Lower 

 Paleozoic rocks in North America. For Newfoundland the succession 

 of the rocks now referred to the Cambrian is Upper Potsdam, Lower 

 Potsdam, and St. John's group, and Newfoundland is cited as the local- 

 ity where the lower portion of the series is complete. The lowest, or 

 St. John's group, is correlated with that of St. John, New Brunswick, 

 and the Paradoxides beds of Braintree, Massachusetts. The lower 

 Potsdam is represented by several hundred feet of limestones and 



1 The student's manual of geology. Second edition. Edinburgh, 1862, p. 457. 



2 Geological survey of Canada, Report, of progress from its commencement to 18G3. Montreal, 1863, 

 pp. 983, 11 plates. Atlas of maps and sections, with an introduction and appendix. Montreal, 1865. 9 

 maps and sections. 



s 0p.cit.,p.288. 



4 0p.cit., p. 293. 



6 Logan, W. E., Lower Silurian Rocks of North America. Geol. Surv. Newfoundland, Rep. Prog, for 

 1864, Montreal, 1866, pp. 45, 46. Revised edition, 1881, p. 49. 



