ANNUAL ADDRESS, MDCCCLXXIII. 29 



vast series of crystalline rocks of gneiss, mica-schist, quartz- 

 ite, and limestone, more than 30,000 feet in thickness, 

 which have been called Laurentian, and which are already 

 known to occupy an area of about 200,000 square miles." 

 (Lyell's Student's Elements, p. 475.) In these are several 

 limestones, one of them from 700 to 1,500 feet thick. 



The most ancient life which the earth possessed has 

 been traced to this limestone. In it has been found that 

 peculiar organism called Eozoon Canadense, which having 

 played an important part in the earliest history of the 

 globe, by building up whole reefs of limestone rock, is a 

 pertinent subject to the present inquiry, and I cannot do 

 better than read Sir Charles Lyell's description of it. At 

 page 475 of his Student's Elements he writes, "In the 

 most massive of these Laurentian limestones Sir W. Logan 

 observed in 1859 what he considered to be an organic 

 body much resembling the Silurian fossil called stromato- 

 pora rugosa. It had been obtained the year before by 

 Mr. McCulloch, at Grand Calumet on the river Ottawa. 

 This fossil was examined in 1864 by Dr. Dawson of 

 Montreal, who detected in it, by the aid of the microscope, 

 the distinct structure of a rhizopod or foraminifer. Dr. 

 Carpenter and Professor T. Rupert Jones have since con- 

 firmed this opinion, comparing the structure to that of 

 the well known nummulite. It appears to have grown 

 one layer over another, and to have formed reefs of 

 limestone as do the living coral-building polyp animals. 

 Parts of the original skeleton, consisting of carbonate of 

 lime, are still preserved, while certain interspaces in 

 the calcareous fossil have been filled up with serpentine 

 and white augite. On this oldest of known organic 

 remains Dr. Dawson has conferred the name of Eozoon 

 Canadense." 



