walcott.] CANADIAN EXTENSION. 115 



used in the construction of buildings, both public and private, and in 

 the fortifications of Quebec, with the gray sandstone terminating the 

 Lorraine section of Jefferson County, New York. 1 These sandstones 

 were subsequently named the Sillery sandstones by Sir W. E. Logan, 

 who at first followed the correlation made by Dr. Emmons, and referred 

 them to the Lorraine shales or Hudson River group. 



In the report of progress for 1843, of the Geological Survey of Canada, 3 

 an account is given in a very general manner of an exploration by Sir 

 W. E. Logan of the rocks on the south shore of the lower St. Lawrence, 

 near Cape Rosier ; and they are further described in the report for 

 1844, as seen from Cape Chat toward Cape Rosier, going down the river. 

 This is followed in the report for 1847-48 3 by a description of the rocks 

 of the extension of the Green Mountains into Canada, and the strata 

 upon the west which are now supposed to be of Cambrian age. They 

 were then referred to the Hudson River group, with the possible addi- 

 tion of the Shawangunk conglomerate. In their extension it is stated 4 

 that these recognized rocks of the Hudson River group have a con- 

 tinuous run from Lake Champlain along the south bank of the St. 

 Lawrence to Cape Rosier. 



In a report on the rocks on the south side of the St. Lawrence, in the 

 report of progress for 1849-'50, 5 a preliminary description is giveu of 

 five masses of rock met with. They include the dark gray slates, gray, 

 green, and occasionally red shales, hard sandstones, and a red and green 

 shale that were subsequently largely referred to the Quebec group by 

 Sir Wm. Logan, and now, in part, to the Cambrian by Dr. R. W. Elis. 

 In a report for 1852-'53 6 a description is given of the strata on the north 

 shore of the St. Lawrence between Cap Rouge River and Quebec. At 

 the base there is a succession of hard, sandy layers, with softer shales 

 that extend along the river shore for some distance, and then thick 

 beds of sandstone separated by thinner bands of red and green shales. 

 The red and green shales have a great thickness further down the river. 

 Mr. Logan says that it would be hazardous to pronounce with confi- 

 dence what it is, from the probably contorted condition of the strata. In 

 regard to the sandstones, however (supposed torepresent theOneidacon- 

 glomerate), no folds have been detected. They are thought to be about 

 900 feet in thickness. This is the first preliminary description of the 

 sandstones and shales that were subsequently referred to the Lanzon 

 and Sillery series of the Quebec group. 7 



1 (J oology of New York, part 2, comprising the survey of the 2d geological (northern) district. 1842, 

 p. 125 



2 [Account of the general structure of an extended area in North, America.] Geological survey Canada, 

 report of progress for 1843. 1845, pp. 6-1?. [Documentary Edition.] 



3 Logan, W. E. Geological survey Canada, report for progress 1847-48. 1849, pp. 2-17 [Documen- 

 tary Edition.] 



«Op. cit , p. 17. 



6 Lo<zan, W. E. | Report on rocks on south side of the St. Lawreuce.] Geological survey Canada 

 report of progress for 1849-50. Toronto, 1850, pp. 32-33. 



"Logan, W. E. [Exploration on the north side of the St. Lawrence, between Montreal and Cape 

 Tourmente.] Geologioal survey Canada, report of progress for 1852-'53, 1854, pp. 5-74. 



7 Op. cit, p. 34. 



