384 THE CAMBRIAN. [bull.8L 



tion of the Coosa Valley shales to the quartzites referred to the Chil- 

 howee formation of Tennessee. The fauna of the shales is large and 

 varied, and should be studied in connection with that of the Cambrian 

 section of Tennessee aud New York. 



Utah and Nevada. — The problems awaiting solution in the study of 

 the Cambrian rocks of Nevada and Utah are of an unusually interesting 

 character. Those that suggest themselves are : 



(1) The study of the basal beds of the Ca mbrian, and the possible ex- 

 tension of the Olenellus fauna down into the quartzite series beneath 

 what is now recognized as the Olenellus zone. From all that is known 

 to me of the rocks in Nevada and Utah, I think that in western central 

 Nevada the best opportunity will be found for the discovery of the 

 faunas preceding the present recognized base of the Cambrian. Dur- 

 ing later Algonkian time there appears to have been a great accumu- 

 lation of arenaceous and siliceous sediments along the line of the Wa- 

 satch and extending westward into central Nevada. In western Nevada 

 they are more shaly and calcareous, and it is possible that the condi- 

 tions under which they were deposited were more favorable for the 

 presence and preservation of the life of that period. 



(2) The careful and detailed study of the great Cambrian section of 

 central Nevada for the purpose of determining the full sequence of life 

 throughout. Our prese nt knowledge of it is very incomplete, and there 

 are many gaps that ca n probably be filled in by detailed work and the 

 careful collection of the fauna in connection with the study of strati- 

 graphy and sedimentation. 



(3) The study of the sections from the Wasatch westward to western 

 Nevada for the purpose of determining the change of sedimentation and 

 life from east to west. 



(4) Another important subject of investigation is the transition be- 

 tween the Upper Cambrian and Ordovician faunas. This has been par- 

 tially worked out in the Eureka district section, but there still remains 

 much to be learned by careful detailed study of the sediments and 

 faunas in the field. 



(5) One of the unsolved problems of Utah is the question of the geo- 

 logical age of the quartzite beneath the Carboniferous limestone sur- 

 rounding the main quartzite series of the Uinta Mountains. It is 

 probable that there is a series of Cambrian rocks beneath the limestone 

 and above the quartzite as in the Big Cottonwood Canon section of the 

 Wasatch Eange ; but it will remain an open question until pa.eonto- 

 logic evidence is obtained. 



Colorado. — Investigation in Colorado should be directed toward dis 

 covering fossils in the strata referred to the Upper Cambrian zone, and 

 to verifying the exact stratigraphic position of the beds carrying 

 Dikelocephalus at Quandary Peak. 



Roclcy Mountains.— In. the eastern district of the Rocky Mountain 

 Province it is desirable that close study should be made of the various 



