466 Reports and Proceedings — 



seeing that the term has been used by so many modern writers, and its 

 exact signification occasionally misunderstood. The imperfection of the 

 palaeontological record is usually understood by the term when used, 

 and it will be considered here as an illustration of the incompleteness 

 of our knowledge of earth-history ; but it must be remembered that the 

 imperfection of the physical record is equally striking, as will be in.-i 

 on more fully in the sequel. 



Specially prominent amongst the points upon which we are ignorant 

 stands the nature of the pre-Cambrian faunas. The extraordinary com- 

 plexity of the earliest known Cambrian fauna has long been a matter for 

 surprise, and the recent discoveries in connection with the Olenellus fauna do 

 not diminish the feeling. 1 After commenting upon the varied nature of 

 the earliest known fauna, the late Professor Huxley, in his Address to the 

 Geological Society in 1862, stated that "any admissible hypothesis of 

 progressive modification must be compatible with persistence without 



progression, through indefinite periods Should such an hypotb 



eventually be proved to be true, .... the conclusion will inevitably present 

 itself, that the Palaeozoic, Mesozoic, and Cainozoic faunae and floras, taken 

 together, bear somewhat the same proportion to the whole series of 

 living beings which have occupied this globe, as the existing fauna and 

 flora do to them." Whether or not this estimate is correct, all geologists 

 will agree that a vast period of time must have elapsed before the 

 Cambrian period, and yet our ignorance of faunas existing prior to the 

 time when the Olenellus fauna occupied the Cambrian seas is almost 

 complete. True, many pre-Cambrian fossils have been described at various 

 times, but, in the opinion of many competent judges, the organic nature 

 of each one of these requires confirmation. I need not, however, enlarge 

 upon this matter, for I am glad to say we have amongst us a geologist 

 who will at a later stage read a paper before this Section upon the 

 subject of pre-Cambrian fossils, and there is no one better able, owing 

 to his intimate acquaintance with the actual relics, to present fairly 

 and impartially the arguments which have been advanced in favour of the 

 organic origin of the objects which have been appealed to as evidences of 

 organisms of pre-Cambrian age than our revered co-worker from Canada, 

 Sir J. W. Dawson. We may look forward with confidence to the future 

 discovery of many faunas older than those of which we now possess certain 

 knowledge, but until these are discovered the palaeontologies! record 

 must be admitted to be in a remarkably incomplete condition. In the 

 meantime, a study of the recent advance of our knowledge of early life 

 is significant of the mode in which still earlier faunas will probably be 

 brought to light In 1845 Dr. E. Emmons described a fossil, now known 

 to be an Olenellus, though at that time the earliest fauna was supposed 

 to be one containing a much later group of organisms, and it was not 

 until Nathorst and Brogger established the position of the Olenellus zone 

 that the existence of a fauna earlier than that of which Paradoxides was 

 a member was admitted ; and, indeed, the Paradoxides fauna itself was 

 proved to be earlier than that containing Olenus, long after these two 

 genera had been made familiar to palaeontologists, the Swedish palaeon- 

 tologist, Angelm, having referred the Paradoxides fauna to a period 

 earlier than that of the one with Olenus. It is quite possible, therefore, 

 that fossils are actually preserved in our museums at the present moment 

 which have been extracted from rocks deposited before the period of 



1 Dr. C. D. Walcott, in his monograph on "The Fauna of the Lower Cambrian 

 or Olenellus Zone" (Washington, 1890), records the following great groups as 

 represented in the Olenellus beds of America: Spongise, Hydrozoa, Actinozoa, 

 Echinodermata, Annelida? (trails, burrows, and tracks), Brachiopoda, Lamelli- 

 hranchiata, Gasteropoda, Pteropoda, Crustacea, and Trilobita. Others are known 

 as occurring in beds of the same age in the Old World. 



