PREFACE 



The manuscript of this paper was left by the late Dr. Charles 

 Doolittle Walcott in such shape that it could be satisfactorily com- 

 pleted. Having been associated with the author in his Cambrian 

 work for almost 13 years, and having conducted some of the investi- 

 gations to obtain the necessary data used in this summary of his 

 stratigraphic studies in the Canadian Rockies, I have undertaken 

 the task of completing and publishing the paper. 



Only such alterations have been made as were contemplated by 

 Dr. Walcott, or that have resulted from plans of procedure we had 

 previously agreed upon. 



From notes and fragments, it appears that Dr. Walcott intended 

 to add a discussion of the structure and of the paleogeography, but 

 neither of these subjects was sufficiently developed to permit me to 

 include the chapters. He had also planned to publish certain correla- 

 tion charts -that I was making, but under the circumstances it is 

 thought best to omit them. 



The present report, which I feel sure will take its place among 

 the outstanding stratigraphic papers, has had a remarkable history. 

 Tt existed in partly finished form for a number of years, always about 

 completed in Dr. Walcott's mind, but since each year's work in the 

 field and laboratory added so much new information, and new prob- 

 lems arose so persistently, the date for sending it to press was re- 

 peatedly advanced, a procedure which, considering the present status 

 of the Cambrian studies, is in no wise out of the ordinary. The 

 remarkable thing was that Dr. Walcott, when well past the age at 

 which many men cease work altogether, put aside this manuscript, 

 took the time to study the newer principles of stratigraphy, and then 

 rewrote the entire work on the new basis ; truly the mark of a great 

 mind. 



Chas. E. Resser. 



March 19, 1928. 



