50 PROCEEDINGS OF THE GEOLOGICAL SOCIETY. [Nov. 19, 



M. Durocher considers local phenomena. But, as we learn from this 

 author, the contact of this formation with Silurian is only seen with 

 perfect distinctness on Lake Miosen*, where the latter is transgressive 

 in a moderate degree, because, in the course of its undulations, 

 the Huronian at that spot has not a high dip. The meeting of the 

 Silurian beds of Hedemark, on the south of Losness, with the Huro- 

 nian or semi- crystalline Azoic rocks is rendered not so clear on 

 account of the undulations of the latter, which have only a moderate 

 dip, and are but feebly crystalline. Nevertheless it is here that it 

 truly takes place. As in Canada, no very clear order of succession 

 has been made out in the individual beds of the Norwegian forma- 

 tion. How could there be, when in both countries plutonic action 

 has been intense, prolonged, and minute in its effects ? 



While these deposits present in their composition notable varia- 

 tions, from place to place, they nevertheless possess in every part of 

 Norway the following common characters. 



This second Azoic, or Huronian, formation is for the most part 

 essentially a schist, argillaceous, chloritic, and micaceous by turns ; 

 changing often also from the foliate and crystalline condition to the 

 amorphous or sedimentary, and this either suddenly or insensibly. 



These schists frequently become siliceous, and then they may be 

 accompanied by granular, compact, and subcompact quartzites ; the 

 latter being translucent, and with a conchoidal fracture. The Gous- 

 tafield quartzitef is remarkably like that of Lake Huron. It is in 

 mountain-masses, as in Canada, where it forms hills, whose sides 

 shine bright and white from amid the dark pines. It is translucent, 

 glassy, and clear ; grey, greenish or bluish grey ; and brittle, 

 granular, or compact. It is also schistose ; a tendency to which 

 structure is increased by interspersed laminse of talc, chlorite, or 

 mica. Certain varieties on the east side of Altenfiord and elsewhere 

 are red, green, violet, and white. Others assume the form of rib- 

 boned jasper (near Hjardal Church) or of hornstone, and become 

 conglomerates and breccias, with a dark-coloured paste, and con- 

 taining boulders of red and white jasper (on the Mandsela River), 

 of quartz, chlorite-slate, and hornblende. Porphyritic intrusions 

 are common among the quartzites, and those of Nummendal and 

 Tellemark yield much sulphuret of copper, specular iron, and mag- 

 netite. 



Besides these schists and quartzites, we have, in Norway, grau- 

 wackes (grits and conglomerates, in fact), conformable to the schists, 

 &c, with a dark-green base, and pebbles of gneiss, granite, quartz, 

 and porphyry ; being the nearest approach, as far as I am aware, 

 to the peculiar greenstone-conglomerate of this age in Canada. We 

 must not always expect identities. 



The Huronian limestone here is not quite equal in quantity to 

 that in Canada, with the exception of that in FinmarkJ, where it is 

 pretty well developed. It is not white, but dark grey or blackish, 



* Memoires de la Soc. Geol. de France, ser. 2, vol. vi. p. 62. 

 t Op. tit. p. 63. + Op. tit p. 98. 



