NO. 5 PRE-DEVONIAN PALEOZOIC FORMATIONS 187 



of all of these sections and many others before stratigraphic and 

 paleontologic correlations of more than a general character can be 

 made for the Cordilleran area. 



Geologists may, perhaps, wonder why I did not acquire many more 

 geological data and larger collections in the Canadian Rockies during 

 the period 1907 to 1925. The answer will be found in the many 

 physical obstacles encountered in the field, such as unfavorable weather 

 (often from one-third to one-half of the short field season would 

 be lost because of rain, snow, or cold) ; long distances to be traveled 

 with pack train ; and last, but not least, the inability of a man of three 

 score years and more to utilize fully the trails of mountain goat and 

 sheep above timber line, where the finest exposures of the strata 

 usually occur. More than three full seasons were devoted to collect- 

 ing a large and unique fauna from the celebrated Burgess shale 

 quarry. In Washington, administrative and public duties demanded 

 so much time and energy that field notes and collections were often 

 inadequately studied and prepared for publication. 



One of the fascinating features of the geology of the Canadian 

 Cordillera is the delightful uncertainty of the results of structural 

 and stratigraphic work. The sections are complicated by irregularities 

 of sedimentation, both longitudinal and transverse, in the secondary 

 troughs of the original Cordilleran Geosyncline, and by both normal 

 and thrust faulting. Great shale deposits thousands of feet in thick- 

 ness like those of the Chancellor formation may be absent in a section 

 a few miles distant or a great calcareous series of shales and lime- 

 stones like the Goodsir may be apparently represented in the sec- 

 tion by limestones of varying character and thickness or be alto- 

 gether absent. Were it not for a few formations like the Lyell of the 

 Cambrian, the Mons of the Ozarkian, and the Messines of the De- 

 vonian, even an approximate idea of the geologic history of this 

 wonderland could only be given by a detailed areal geologic map with 

 structural sections, based on thorough study of the formations, their 

 sedimentation, and contained fossil remains. My study of it has been 

 of the nature of a reconnaissance, made with the view of furnishing 

 to the future areal and structural geologist some additional data on 

 the succession of the pre-Devonian fossil faunas and faunules in the 

 various sedimentary formations that collectively form one of the 

 great pre-Devonian sections of the world. 



Acknowledgments. — In a previous paper ^ I have acknowledged my 

 indebtedness to Dr. Rudolf Ruedemann of the New York State Mu- 



' Smithsonian Misc. Coll., Vol. 75, No. i, 1924, p. 7. 



