318 THE CAMBRIAN. |bull.81. 



Feet. 



(19) (a) Buff, sandy shale 40 



(&) Gray arenaceous limestone 30 



(c) Sandy, calcareous shale 3 



73 



(20) (a) Massive-bedded, bluish gray limestone 200 



Fragments of fossils. 

 (6) Compact gray siliceous limestoue, almost quartzite in some places 400 



(c) Bluish black, evenly bedded limestone 6 



006 



Strike N. 30° W., dip. 10° E. 



(21) Buff to pinkish argillaceous shale, with fossils, and a few interbedded lay- 



ers of limestone from 3 to 15 inches thick 125 



Fossils: Eocys1ite8 ?? longidactylw, Lingulella ella, Kutorgina pannula, 

 Hyolilhes billingsi, Ptychoparia piochensis, Olenoides typically 

 Bathyuriscus howelli, and B. producta, 



(22) Massive-bedded, siliceous limestone ; weathering rough and broken into 



great belts, 200 to 300 feet thick, by bands of color in light-gray, 

 dark-lead to bluish black; on some of the cliff faces the weathered 

 surface is reddish 1, 570 



(23) Bluish black limestone in massive strata, that break up into shaly layers 



on exposure to the weather. The latter feature is less distinct 850 

 feet up, aud the limestone becomes more siliceous, with occasional 



shaly beds 1, 430 



Fossils; near the summit specimens were found that are referred to 

 Ptychoparia minor. 



Quite a fauna occurs in 23^as found one mile farther south an the line of the sec- 

 tion. 



Summary of section. 



Feet. 



1. Quartzite 350 



2. Limestone and shales (argillaceous and arenaceous) 1,450 



3. Massive limestones 3, 000 



Total 4.800 



As in the Eureka section, the species of Olenellus have a very nar- 

 row range near the base of the limestone series above the quartzite. 



The fauna found in No. 21 of the section materially strengthens the 

 correlation of the fauna of the Prospect Mountain limestone and the 

 Secret Canon shale with that of the Paradoxides zone of the Atlantic 

 Basin. 



The fauna of the great limestone belt above 23 of the section is rep- 

 resented by only a few specimens on the line of the section. A mile 

 south, however, on the strike of the strata a strongly marked Upper 

 Cambrian (Potsdam) fauna occurs. The species identified are as fol- 

 lows: 



Bellerophon antiquatus. Dicellocephalus sp.? 



Pleurotomaria, 3 undt. sp. Ptychoparia (Euloma?) dissimilis 



Hyolithes, 3 n. sp. P. sp.? 



Dicellocephalus pepinensis. Arethusina americana. 



D. (type of D. miunesotcnsis). Illaenurus sp.? 



Of this fauna two species are identical with those from the higher Potsdam fauna 

 at Eureka, viz : Ptychoparia (2?.?) dissimilis and Arethusina americana ; and Bellerophon 

 antiquatus, and Dicellocephalus pepinensis occur in the upper Potsdam of Wisconsin 



