1865] LOGAN — LAURENTIAN FOSSILS. 93 



The united thickness of these two groups in Canada cannot be 

 less than 30,000 feet, and probably much exceeds it. The Lau- 

 rentian of the west of Scotland, according to Sir Roderick Mur- 

 chison, also attains a great thickness. In that region the Upper 

 Laurentian or Labrador series, has not yet been separately recog- 

 nized ; but from Mr. McCulloch's description, as well as from the 

 specimens collected by him, and now in the Museum of the Geolo- 

 gical Society of London, it can scarcely be doubted that the Labra- 

 dor series occurs in Skye.* The labradorite and hypersthene rocks 

 from that island are identical, with those of the Labrador series in 

 Canada and New York, and unlike those of any formation at any 

 other known horizon. This resemblance did not escape the notice 

 of Emmons, who, in his description of the Adirondack Mountains, 

 referred these rocks to the hypersthene rock of McCulloch, although 

 these observers, on the opposite sides of the Atlantic, looked upon 

 them as unstratified. In the Canadian Naturalist for 1862, 

 Mr. Thomas Macfarlane, for some time resident in Norway, and 

 now in Canada, drew attention to the striking resemblance between 

 the Norwegian primitive gneiss formation, as described by Nau- 

 mann and Keilhau, and observed by himself, and the Laurentian, 

 including the Labrador group ; and the equally remarkable simi- 

 larity of the lower part of the primitive slate formation to the 

 Huronian series, which is a third Canadian group. These prim- 

 itive series attain a great thickness in the north of Europe, and 

 constitute the main features of Scandinavian geology. 



In Bavaria and Bohemia there is an ancient gneissic series. 

 After the labours in Scotland, by which he was the first to estab- 

 lish a Laurentian equivalent in the British Isles, Sir Roderick 

 Murchison, turning his attention to this central European mass, 

 placed it on the same horizon. These rocks, underlying Barrande's 

 Primordial zone, with a great development of intervening clay-slate, 

 extend southward in breadth to the banks of the Danube, with a 

 prevailing dip towards the Silurian strata. They had previously 



[* This was first shown by Mr. T. Sterry Hunt, after his examinations 

 of Me'Julloch's collections, in a paper published in the Dublin Quar. 

 Journal of Science for 1863, p. 230. See also Silliman's Journal [2] 

 xxxvi. 226, and Canadian Naturalist, vi. 208. Prof. Haughton of Dub- 

 lin has since visited the islands of Skye and Iona, and confirmed the 

 observations of Mr. Hunt. See Proc, of the Royal Geological Society 

 of Dublin for Dec. 14, 1864, in the Geol. Magazine for February, 1865, 

 page 73. — Eds.] 



