ART. 21 OBDOVICIAN TEILOBITES — ULKICH 71 



Canadian formations. In short, we are prepared to give an alto- 

 gether new and very different account of Oklahoma stratigraphy 

 that moreover throws much new light on the interpretation of geo- 

 logical events in other parts of the continent. 



As details regarding the results of these studies will probably be 

 published in the near future their further anticipation here seems 

 undesirable. What has been said sufficiently indicates the progress 

 that is being made in working out the broader aspects of the Pale- 

 ozoic history of the middle part of the Mississippi Valley region. 

 Great progress is being made also in the already much better known 

 Upper Mississippi Valley region. The results of these investiga- 

 tions, which comprise much more detailed information regarding the 

 paleontology of especially the Cambrian, Ozarkian, and Canadian 

 deposits than is now available in published form, is also being 

 prepared in collaboration with others for early publication. 

 Nor are the results of continued investigations in the Cordilleran 

 province that were begun by Walcott and inherited by Dr. Charles 

 E. Resser and myself falling short of expectations. In fact, the 

 stratigraphic and extremely abundant faunal data from all of these 

 regions are being studied concurrently. 



Finally, as regards the Appalachian region, the years of painstak- 

 ing labor bestowed on it by Dr. Charles Butts are correcting, supple- 

 menting, and gradually filling in the details of work begun by me 

 nearly 30 years ago and partlj'^ published in 1911. Hundreds of 

 pages filled with notes on redefinitions of formations and new posi- 

 tions assigned to them in the correlation tables and detailed descrip- 

 tions of sections and faunal lists, which had been written and sub- 

 mitted with the discussion of principles and criteria of stratigraphic 

 correlation that was then published under the title Revision of the 

 Paleozoic Systems, remain unpublished to this day. With the help 

 of Dr. R. S. Bassler, who assisted me in the field during parts of the 

 ten years mainly devoted to stratigraphic investigations in the Ap- 

 palachian Valley, much of this neglected manuscript will be revised 

 to meet present-day requirements and again submitted with subse- 

 quent observations for publication. In the meantime results of Doc- 

 tor Butts' investigations in the southern end of the valley have been 

 published by the United States Geological Survey in the Birming- 

 ham Folio and more fully in the volume published by the State on 

 the Geology of Alabama (1922). During the past two years he has 

 been engaged on the Virginia part of the valley. His work here is 

 disclosing an astounding amount and variety of highly interesting 

 and important details as regards the distribution of f ormational units, 

 stratigraphic overlaps, and consequent local variations in the sequence 

 of beds and the geologic structure of the area. 



