358 Sm WILLIA]\I EDMOXD LOGAX. 



credit of careful and original observations on the subject, which he sub- 

 sequently extended to the coal-fields of Nova Scotia and Pennsj-lvauia, 

 which were visited by him in 1841. In 1842, he was offered the 

 direction of a geological survey of Canada, which he accepted, begin- 

 ning his work in the spring of 1843, with the aid of Mr. Alexander 

 INIurray, now director of the geological survey of Newfoundland. It 

 was nut till four years later that he was joined by Dr. T. Sterry 

 Hunt. The labors of Logan for 1843 and 1844 were directed to the 

 coal basin of Nova Scotia and New Brunswick and to the paleozoic 

 formations of the adjacent peninsula of Gaspe, and included his study 

 of the now fiimous section of the Joggins at the head of the Bay of 

 Fundy, where over 14,000 feet of coal measures, hicluding seventy-six 

 coal seams, are displayed in unbroken sequence. In 1845, his atten- 

 tion was turned to the more ancient rocks which appear on the 

 Ottawa River and its tributaries; and in 1846 he made with Mr. 

 Murray a preliminary survey of the geology of the north shore of 

 Lake Superior. 



It is with the ancient crystalline rocks that his name will be chiefly 

 associated, and especially with the formations since called Laurentiau 

 and Huronian ; and it may be well in this connection to state briefly 

 the results of their examination by the Canadian survey, wliich now 

 belong to the history of geological science. The gneissic character of 

 the crystalline rocks which were known to underlie the paleozoic for- 

 mations in northern New York and Canada had long been recognized; 

 but the prevalent view with regard to such gneissic rocks, both there 

 and elsewhere, was that expressed by Emmons, who had carefully 

 studied them in the first-named region, that they were igneous or 

 fire-formed rocks, the laminated structure of which is not due to 

 the intervention of water. He maintained that they were in no sense 

 of sedimentary origin, and included no sedimentary layers, a view to 

 which some recent writers still incline. In the first year of the 

 Canadian survey, however, Mr. Murray (in his report published in 

 1844), having studied these rocks to the north of Lake Ontario, de- 

 clared that these granites and gneisses (the extension of those of the 

 Adirondacks) "present evidences of stratification," and were therefore 

 to be regarded not as primary, but rather as " met^unorphic " rocks ; a 

 term which had been proposed l)y Lyell to designate crystalline sedi- 

 mentary strata. In the subsequent i-eport of Logan, who examined 

 the same rocks on the Ottawa in 1845, and puldished his report in 

 1847, they were again described as " metamdrphic rocks, .... ap- 

 ])ariiitly of sedimentary origin, chiefly syeuitic gneiss with crystalline 



