126 THE CANADIAN NATURALIST. [Yol X. 



their icquiries, .-is well as some special reports forwarded to him 

 by individuals. The Congress did not, however, pass on to the 

 discussion of these matters; but the manner in which the Eno-Hsh 

 Committee were organizing their work met with the approval o^ 

 the Congress, and a vote was passed that the other countries 

 should adopt a similar plan, and form sub-committees for the in- 

 vestigation of the several groups. He was further unofficially 

 recjuested to get the reports printed as soon as possible, in order 

 to facilitate discussion, and with a view to arrivino- at an under- 

 standing upon the simpler questions before the next meeting of 

 the Congress. This was appointed to be held at Berlin in 1884. 

 The following Congress will be held in England. 



PRE-CAMBRIAN ROCKS. 



Dr. T. Sterry Hunt gave some account of the pre-Cambrian 

 or Eozoic rocks of Euroj-e as compared with those of North 

 America. He liad on several occasions studied them, both on 

 the continent and in the British Isles, especially with Dr. Hicks 

 in Wales in 1878. In North America the recognised base is a 

 highly granitoid gneiss, without observed limestones, which he 

 has called the Ottawa gneiss, overlain, probably uuconformably, 

 by the Grenville series of Logan, consisting chiefly of granitoid 

 gneisses, with crystalline limestones and quartzites. These two 

 divisions make up the J^aurentian of Canada, and correspond 

 respectively to the Lewisian and the Dimetian of Hicks. Rest- 

 ing in discordance on the Laurentian, we find areas of the Norian 

 or Labrador series (Upper Laurentian of Logan), chiefly made up 

 of anortholite rooks, granitoid orgueissoid in texture, with some 

 true gneisses. The Huronian is seen to rest unconformably on the 

 Laurentian, fragments of which abound in the Huronian conglome- 

 rates. To the lower portion of the Huronian the speaker had 

 formerly referred a great series of petrosilex or hiilleflinta rocks, 

 described as inchoate gneisses, passing into petrosilex-porphy- 

 ries, occasionally interstratified with quartzites. This series, in 

 many places wanting both in Europe and America, he is now 

 satisfied forms an underlying unconformable group — the Arvo- 

 nian of Hicks, Above the Huronian is the 2;reat iMontalbau 

 series, consisting of grey tender gneisses and quartzose-schists, 

 both abounding in muscovite, occasionally with hornblendic 

 rocks. The Pebidian of Hicks includes both the Huronian and 

 the Montalban, to which latter belong, according to the speaker, 

 certain gneisses and mica-schists both in Scotland and in Ireland, 



