126 RELICS OF PRIMEVAL LIFE 



Logan was, however, a man not to be daunted by 

 an unsolved problem, even though the facts for its 

 solution must be sought in a wilderness known to few 

 except adventurous trappers, hunters, and lumber- 

 men ; and he soon learned that this ancient gneissic 

 formation contained other rocks beside gneiss, more 

 especially thick and extensive limestones, and that 

 its beds seemed to have a definite arrangement, and 

 could be traced over great areas. He addressed 

 himself, therefore, to the problem of unravelling the 

 tangled " complex," and with a few hardy assistants, 

 spent years in laboriously tracing its beds along 

 river courses and over mountains, and in mapping, 

 in a manner never previously attempted, its several 

 members, designating at the same time the whole by 

 the term " Laurentian," because it constituted the 

 mass of the hills lying north of the St. Lawrence, 

 called by old French geographers the Laurentides, 

 and separating the St. Lawrence Valley and the 

 region of the great lakes from Hudson's Bay and the 

 Arctic Sea. In this manner he laid a foundation, 

 which still remains unshaken, for the geology of the 

 oldest rocks, and prepared the way for the discovery 

 of the forms afterward named Eozoon Canadense. 

 At the same time Dr. Sterry Hunt, the chemist of 



