0. H. Hershey — Belt and Pelona Series. 269 



Estimated thickness 



26. Green and black slate 400 feet 



27. Brown and pink quartzite - 300 " 



28. Dark gray slate weathering dark brown. 500 " 



29. White, hard, fine conglomerate 50 " 



30. Reddish brown, weathering dark gray, 



micaceous schistose slate — ],500 " 



31. Black schistose slate.-. 500 " 



(Underlaid by intrusive granite) 



Total 15,550 to 23,850 feet 



Small collections of fossils were sent to the United States 

 Geological Survey, but I am so far separated from the reports 

 on them, that I will merely make the statement that Olenellus 

 was found in the limestones at a considerable height above 

 the base, particularly in No. 17, if I remember rightly. At 

 any rate, there is over 1,000 feet of undoubted Lower Cam- 

 brian limestones and shales. These pass by the transition 

 formation, No. 20, into a great series of quartzites and slates, 

 which appeared to me to be conformable throughout, though 

 several conglomerate bands were observed. The lithologic 

 characters are similar from the base of the limestones down, 

 strongly suggesting a single series of sediments. There is no 

 sharp break in the apparent degree of alteration, but in a gen- 

 eral way a progressive increase in the metamorphism down- 

 ward. Thus, Nos. 30 and 31 mark the approach to the stage 

 of metamorphism reached by the crystalline schists. I was of 

 the impression that the entire series represents continuous 

 sedimentation and I classed all the strata under the Lower 

 Cambrian limestone as also Lower Cambrian, though I recog- 

 nized that this would give the Lower Cambrian period dispro- 

 portionate length. Since becoming acquainted with the Belt 

 rocks of Idaho, I have been impressed by a marked resem- 

 blance in a general way between them and this Nevada quartz- 

 ite-slate series, not only in character of sediments but in degree 

 of alteration. In both regions, quartzites predominate above 

 and black slaty rocks below. The alteration (by regional 

 metamorphic action) is slightly greater in the Nevada section 

 than in that of Idaho. 



This pre-Olenellus quartzite-slate series in Nevada may, 

 doubtless, be correlated in a general way with the similar 

 series in the Wasatch Mountains. Walcott regarded the latter 

 as conformable and arbitrarily drew a line beneath which he 

 considered the rocks as Algonkian. Blackwelder, however, 

 has found evidence of a nonconformity that may be taken as 

 a convenient plane separating the Lower Cambrian and Belt 

 series. The same nonconformity may be marked by the white 



