84 THE CANADIAN NATURALIST. [Dec. 



or variegated, which I called the Bojian gneiss. This difference 

 of opinion is however at once removed by the remark that I did 

 not intend to maintain in the older gneiss the existence of a 

 formation more ancient than the fundamental gneiss of Scotland, 

 nor yet to assimilate the newer or grey gneiss to the more recent 

 or so-called metamorphic series, which, according to Sir Roderick, 

 may be clearly distinguished in Scotland from the Laurentian 

 gneiss. 



[This newer gneissic formation of the Highands is, according 

 to Murchison, Ramsay and others, of Lower Silurian age. Our 

 author simply claims to have established a division in the proper 

 Laurentian rocks of Bavaria and Bohemia. It will be seen 

 from the recently published maps of the Laurentian region of the 

 Ottawa, that Sir William Logan there distinguishes three great 

 limestone formations, by which the enormous mass of Laurentian 

 gneiss is separated into four divisions. One or two of the upper 

 ones of these may be eventually found to correspond to the grey 

 Hercynian gneiss of Bavaria, which is there accompanied by the 

 Eozoon Canadense, a fossil so far as yet known characterizing the 

 highest of the three Laurentian limestones. This grey gneiss 

 of Bavaria appears to be lithologically distinct from the Labrador 

 (or Upper Laurentian) series ; nor do we find in the present 

 memoir of Gumbel, any clear evidence of the occurrence either of 

 this, or of the Huronian system, in Bavaria. — T. S. H. 



After citing in this connection Sir W. E. Logan's observations 

 on these ancient formations, which are shown, by the results of the 

 Canadian Survey, to represent three great systems of sedimentary 

 rocks, formed under conditions not unlike those of more modern 

 formations, our author observes : — ] 



Accepting these views of the older Canadian rocks, it would 

 naturally follow that organic life might be expected to reach back 

 much farther than the so-called primordial fauna of Lower 

 Silurian age, and to mark the period hitherto designated as Azoic. 



Guided by these ideas, the geologists of Canada zealously sought 

 for traces of organic life in the primitive rocks of that country. 

 Dr. Sterry Hunt had already concluded that it must have existed 

 in the Laurentian period, from the presence of beds of iron ore, 

 and of metallic sulphurets, which, not less than the occurrence of 

 graphite, were to him chemical evidences of an already existing 

 vegetation, when at length direct evidence of life was obtained by 

 the discovery of apparently organic forms in the great beds of 



