WALC0TT.) 



SUMMARY — IDAHO. 



321 



Feet. 

 130 



315 



quartzitic sandstone beneath is spoken of as occupying the relative 

 position of the Potsdam, although he subsequently refers to it as a 

 part of the true Quebec. 1 Mr. F. B. Meek agreed with Prof. Bradley 

 that the tauna belonged to the Quebec horizon ; and he 2 described 

 Bathyurellus (Asaphiscus) bradleyi and Asaphus (Megalaspis ?) goniocer- 

 ens. The latter species probably comes from the upper portion of the 

 limestone referred to the Quebec group by Prof. Bradley. 



From the data obtained by Dr. A. 0. Peale of the Gallatin River Cam- 

 brian, and our more accurate knowledge of the fauna of the Quebec 

 group, the faunas occurring in the lower portion of the limestone at 

 Malade City are referred to the Upper Cambrian, and those from the 

 upper portion of the limestone to a portion of the Lower Silurian (Or- 

 doviciau). In this connection reference should be made by the reader 

 to Prof. Orestes St. John's work upon the same beds in Wyoming. 



Near the south end of Portneuf Range, north of Malade City, Dr. A. 

 C. Peale measured the following section : 3 



Top. 



1. Blue limestone 



2. Laminated blue limestones, with Conocoryphe, Dikellocephalus, 



Obolella, and two species of Batbyurns 



3. Bluish gray limestones 



4. Laminated limestones, with bands of greenish shales in the upper ) 



portion. The limestones are separated by shaly layers. The 

 limestones are fossiliferous at the base, containing quantities 

 of a trilobite like Conocoryphe. The limestone resembles an 

 oolite, but the structure is probably due to the presence of . 

 some peculiar organic remains. Fragments of Discina were 

 seen - 



5. Rather massive limestones 



6. Laminated blue limestones, in bands of from 1 to 2 inches thick- 



ness, the surfaces of which are yellow-stained. 



7. Rather massi ve li mestones 



8. Green shales or slates, 15 feet 



9. Bluish gray limestone 



10. Bluish limestones, with bands of shales 



11. Massive blue limestones. The dip here appears to be about 40°. .. 



12. Laminated limestones with interlamiuated green shales 



13. Greenish sandstones and shales, passing below into silvery gray 



slates 



14. Slates and shales with a band of limestone about the middle 



15. Blue limestones with irregular structure. The strike is about 



south 5° east, and beyond the station it appears to curve to the 

 south; dip is 60° 



16. Rusty yellow quartzite 



17. Gray and yellowish quartzites 



18. Greenish gray slates 



19. Rusty yellow quartzite, somewhat conglomeritic and containing a 



considerable percentage of iron 



20. Rusty quartzites, about 



21. White quartzites i 



22. Pink and white quartzites $ 



23. Red slates, thickness not taken 



120 



118 



155 



100 

 70 



210 

 185 



70 

 150 

 450 

 180 



130 



600 



500 to 600 



Total 3,483to3,583 



1 Report of Frank H. Bradley, geologist of the Snake River division. U. S. Geol. Surv. of the Terr., 

 6th Ann. Rep., 1873, p. 201. 



2 Preliminary paleontological report ; with remarks on the ages of the rocks, etc. TJ. S. Geol. Surv. 

 of the Terr., embracing portions of Montana, Idaho, Wyoming, and Utah, 6th Ann. Rep., Ibid. 1873, pp. 

 480-485. 



s Report on the geology of the Green River Distriot. TJ. S. Geol. Surv. of the Terr., 11th Ann. Rep., 

 1879, p. 508. 



Bull. 81 21 



