lyiii PROCEEDINGS OF THE GEOLOGICAL SOCIETY. 



I cannot, however, pass over the paper of Sir "W. E. Logan, " On 

 the Occurrence of Organic Remains in the Laurentian Rocks of 

 Canada." These Laurentian rocks consist principally of gneiss, 

 and are now admitted to be amongst, if not, the oldest-known 

 metamorphic rocks on the surface of our globe. 



The existence of these rocks in the British Islands was first 

 pointed out by Sir E. Murchison in Sutherlandshire and Ross-shire 

 as far back as 1858, when he applied to them the term of Funda- 

 mental Gneiss, and described them as having a N.N.W. and 

 S.S.E. strike, almost at right angles with the prevailing strike of 

 all the other and younger metamorphic rocks of the British Isles. 

 In the sketch-map of the North of Scotland which accompanies 

 a subsequent memoir published in the following year, this funda- 

 mental gneiss is described as the Laurentian gneiss of Canada ; 

 and again in 1861, in a paper by Sir R. Murchison and Mr. 

 Greikie, it is generally described as the Laurentian or older 

 gneiss ; and the remarkable N.W. and S.E. strike is alluded to 

 as persistent both on the mainland and in the Hebrides. This 

 formation also covers a large area in Scandinavia ; and certain 

 gneissic rocks in Bohemia and Bavaria, previously divided by 

 Griimbel and Crejci into two series, are referred by Sir R. Mur- 

 chison to the same Laurentian group. And in a paper recently 

 read before this Society, Dr. HoU has suggested the existence of 

 this Laurentian or pre-Cambrian series as forming the nucleus of 

 the Malvern HiUs. 



The Laurentian formation of Canada has been subdivided into 

 two groups, named respectively the Upper and Lower Laurentian, 

 the united thickness of which cannot be less than 30,000 feet. 

 Zones or bands of limestone of great thickness are known to 

 occur in both, and at least three such bands have been ascertained 

 to belong to the lower group. Now it had been stated, more or 

 less vaguely during the last few years, that organic remains had 

 been discovered in these Laurentian rocks, but it was reserved 

 for Sir "W. Logan to bring the first notice of this discovery before 

 the Society in a paper read on the 23rd November last, but which 

 had already been communicated to the British Association at 

 Bath in September. It is accompanied by a paper by Dr. Daw- 

 son, on the Structure of these Organic Remains, with a Note 

 by Dr. Carpenter ; and another paper by Mr. Sterry Hunt, on 

 the Mineralogy of these same Organic Remains. After describing 

 the localities where, and the circumstances under which these fossili- 

 ferous beds were formed. Sir W. Logan shows how recent investi- 

 gations have resulted in the discovery of distinct organic remains 

 in the limestone-bands at the Grand Calumet on the River Ottawa, 

 and at Grenville and Burgess in Canada. These were at first 

 supposed to be corals, but, with the aid of the microscope, such 

 evidence of organic structure has been obtained, that Dr. Dawson 

 has identified the fossil as a Foraminifer growing in large sessile 

 patches, after the manner of Polytrema and Gaiyenteria, but of 

 much greater dimensions. Its peculiar characteristics are (1) small 



