EVIDENCES OF PRIMITIVE LIFE WALCOTT. 255 



CAMBRO-ORDOVICIAN BOUNDARY WEST OF CONTINENTAL DIVIDE.* 



As a third instance of similar kind, the discovery of fairly well- 

 characterized specimens of the trilobitic genus Ceratofijge associated 

 with brachiopods of the same general type as those found in the 

 Ceratopyge shale of Sweden is most important, as it gives the first 

 definite suggestion of a base for the Ordovician in the section along 

 the Canadian Pacific Railway west of the Continental Divide. In 

 Sweden the Ceratopyge shale and limestone are now by general 

 assent placed at the base of the Ordovician, and with our knowledge 

 of the stratigraphy of the upper portion as determined by Mr. Allan - 

 I am inclined to agree with him in placing, at least tentatively, the 

 boundary between the Cambrian and the Ordovician at the summit 

 of the Ottertail limestone and the base of the Goodsir formation. 



The broad question of the Cambro-Ordovician boundary in other 

 sections of North America is one that is still in process of adjust- 

 ment, owing to the absence of detailed information as to the boun- 

 daries between formations and the character of the faunas in the 

 formations. Investigations now in hand will throw new light on 

 the relations of the Appalachian formations and their invertebrate 

 faunas.^ 



CONCLUSION. 



The varied investigations of the past few years have opened very 

 interesting problems which have been barely touched upon in this 

 brief review. 



How much earlier than the pre-Cambrian and Algonkian faunas 

 the study of primitive life may be extended will depend very largely 

 upon the discovery and study of now unknown fossil faunas and 

 floras. All of this comparative study requires a world-wide activity 

 in the fields of geology and paleontology. That science is universal 

 is shown by a recent incident. The writer lately received a scientific 

 pamphlet from a European paleontologist, with the request that it 

 be forwarded to a fellow paleontologist in a country with which his 

 nation was at war, and there was no communication between the two. 

 The friend replied, through the intermediary, acknowledging its 

 receipt and asking that his thanks and kind wishes be conveyed to 

 the sender. 



Students and investigators everywhere are invited to cooperate 

 with the writer in his studies of the evidences of primitive life, and 

 in his effort to correlate all procurable data on the subject and make 

 them available for study and research by all those interested in these 

 fascinating problems. 



1 Smithsonian Misc. Coll., vol. 57, no. 7, 1912. 



= Allan, John A. : Ice River District, British Columbia, Geol. Survey of Canada, Sum. 

 Rept., Dept. of Mines, 1910, pub. 1911, pp. 135-144. 



s Smithsonian Misc. Coll., vol. 64, no. 3, 1916, Cambrian Trilobites. 



