26 I.OVAL SOCIETY OF CANADA 



discussion on tliis subject has arisen. The sedimentary origin of the 

 Anortliosites was maintained for some years, in fact till after 1878 when 

 the first statement on the part of the officers of the Geological Survey, 

 indicating a change of opinion in this direction, appeared. The ac- 

 cepted relationship of the rocks of the anorthosite division to the rest 

 of the Lauren tia II proper was however called in question by Dr. Selwyn, 

 in a report for the year 1877-78, where in propounding a new scheme 

 of classification for the Canadian rocks, he recast the several divisions 

 of the Laurentian and Iluionian, confining tlie former strictly to the 

 great masses of granite-gneiss which were devoid of all traces of sedi- 

 mentation in the form of limestones, slates and conglomerates, while in 

 the Huroiiian he placed the rocks of the Hastings and Grenville series, 

 as also the supposed upper Laurentian or Norian, a name which had 

 been applied by Hunt to the Labradorite rocks. 



In this scheme Selwyn also included in the Huronian the typical or 

 original Huronian of Lake Superior and the conformably — or uncon- 

 formably, as the case may be — overlying upper Copper-bearing rocks, 

 the altered Quebec group, and certain areas between Lake Metapedia 

 and Gaspé, as well as the Cape Breton, the iSTova Scotia and Xew Bruns- 

 wick sub-crystalline and gneissoid groups. 



The opinion that these peculiar anorthosite rocks were not sedi- 

 mentary in their origin had, however, been clearly expressed by various 

 geologists, both in England and America, at a very early date. Among 

 tlie earliest and strongest supporters of their igneous nature may be 

 mentioned Macculloch, who had studied similar rocks in the western 

 isles of Scotland, and Emmons who had investigated their relations to 

 the other crystalline rocks in the state of New York. Packard also, in 

 a paper before the Boston Natural History Society in IS'JS, 

 maintained their igneous rather than their sedimentary origin ; while 

 Hitchcock, in his studies of similar masses in the White Mountains, came 

 to the same conclusions, and Kjeruif and Dalil, from their examinations 

 in Norway of similar rocks also expressed their convictions that they 

 were igneous in tlieir character. 



l)r. Selwyn, in his paper of 1877, in discussing the question of the 

 anortliosites, and their relations to the gneiss and limestone series, also 

 ([uotcs Professor James Hall, of the New York Survey, as stating that 

 " the limestones of Essex and adjoining counties in New York state, do 

 not belong to the Laurentian system, either lower or upper." " The 

 facts on which a part of this conclusion is based, viz., the unconformity 

 of the Laurentian limestone scries to the lower orthoclase gneiss, agree 

 with those of Mr. Vennor, and there is, I think, but little doubt that all 

 these crystalline limestone groups, that is, those of Essex and St. Law- 



