On the Structure and Position of Eozoon Canadense. 283 



If Professor Phillips had introduced into this table the far 

 richer fauna of the Upper Cambrian strata in Bohemia, the 

 comparative poverty of organic life in that epoch would have 

 seemed less striking ; but, on the other hand, the diminution 

 in the number of types as we pass from the Upper to the 

 Lower Cambrian, would have been still more obvious. ff No 

 doubt/' he remarks, "it is open to any one to compare this 

 approach to a Hypozoic zero with the reductions of life to a 

 minimum above the Palaeozoic, and above .the Mesozoic de- 

 posits ; and to suppose that below the Palaeozoics were other 

 earlier strata, and earlier systems of life, though they are now 

 all lost in the general metamorphism which has produced the 

 gneiss and mica schist. No one is likely to believe this, 

 however, who attends seriously to the facts regarding the suc- 

 cessive appearance of the classes, orders, families, genera, and 

 species, as we search the records of geological time." More 

 philosophical in its appreciation of what Mr. Darwin calls " the 

 imperfection of the geological record," and more true as the 

 event has proved, was the remark of Sir C. Lyell upon the 

 " primordial " assumption of M. Barrande — " I have been 

 opposed from the first to a nomenclature the adoption of 

 which would seem to imply the acceptance of such a theory ; 

 for I always felt sure, on contemplating the past history of 

 geology, that we had not yet pushed our inquiries into the 

 past so far as to lead us to despair of extending our discoveries 

 at some future day, when vast portions of the globe hitherto 

 unexplored should have been thoroughly surveyed." 



This sagacious anticipation has been marvellously verified 

 by the discoveries which the excellent geologists of our Canadian 

 survey, under the able direction of Sir William Logan, have 

 recently made in the region of which the exploration was com- 

 mitted to them : for they have shown that the rocks which 

 compose the Laurentian mountains in Canada, and the Adiron- 

 dacks in New York, spreading over an area of about 200,000 

 square miles, belong to a system distinct from and antece- 

 dent to the Cambrian, just as the Cambrian form a system 

 distinct from and antecedent to the Silurian.* These Laurentian 

 strata consist chiefly of quartzose, aluminous, and argillaceous 

 rocks, like the sedimentary deposits of less ancient times ; but 

 for the most part in a condition of metamorphism which has 

 given them a crystalline character. By a break in the con- 

 tinuity of the strata they are marked out into two distinct 

 groups, the Upper or Labrador series resting unconformably 

 on the Lower; and the united thickness of these groups in 

 Canada is certainly not less than 30,000 feet, and probably 



* See the Quarterly Journal of the Geological Society, February, 1865, 

 pp. 45—50. 



