PEAUE.] DESCRIPTIVE GEOLOGY BEAK LAKE PLATEAU. 585 



Base. TMckness in feet. 



4. Eed sandstones, with mterlaminated brick-red shales } gg 



5. Purplish limestones > 



6. Space covered by a red debris, over which bowlders of white quartzite arei 



scattered. The angle of dip in the beds up to this point is 40° to southwest. 



The strike of the beds is north 2° west ._ > 200 



7. Dull puri)lish-red, coarse sandstones, with about 15 feet of light-colored 



siliceous sandstone at the base J 



8. Space iu which beds are covered } 3^ 



9. Coarse, yellowish sandstone ) 



10. Space covered (probably sandstones) 100 



11. White limestone, shaly at the base, and having a yellow band near the top. 



The strike is north 7° east ,• dip, C0° to the northwest 40 



12. Space in which beds are covered by a reddish debris, among which frag- 



ments of limestone are found 540 



13. Gray limestones, with indistinct fossils, amongwhichthe following have been 



identified : Eumicroiis curia, Aviculopeeten idahoensis 90 



14. Bluish-gray limestones, with bands of sandstone. The limestones are fossil- 



iferous, containing the same fossils that are found in layer No. 13 80 



15. Gray-blue limestones like No. 14. The strike is north 9° east ; dip, 60° to 



the northwest 150 



16. Space in which the beds, which are covered, are probably limestones and 



shales, as indicated by a few obscure outcrops 490 



17. Laminated limestone in thin bands, with shaly layers covered in many 



places with a yellowish debris 180 



18. Space in which the beds are concealed 70 



19. Bluish and white limestones, containing traces of fossils like those in layers 



Nos. 13 and 14 - 50 



20. Covered space, probably underlaid with limestones ^ 



21. Limestones and shales 



22. Space in which the beds are concealed 



23. Blue limestones > 680 



24. White quartzite, dipping 35° north of west 



25. Space underlaid by quartzites ? 



23. White limestones, weathering very white and pink on exposed surfaces. . . 



Total 2 981 



On layer ISTo. 26 a location was made. Looking south from tliis point, 

 the ridges into which the beds have weathered appear to run out under 

 Bear Lake. 



Station 101 is located 3^ miles north of Station 100, and is on red 

 sandstones. Between the stations there appears to be a deflection to 

 the eastward in the strike of the sandstones. 



As we have seen, all the beds in the section have dips to the north- 

 west. The beds, therefore, must be a portion at least of the western 

 side of the anticlinal, the axis of which is seen in that portion of the 

 canon of Bear Eiver where the river is flowing almost due north. 



On the north side of the Bear, about due north of Station 101, there 

 is an outcrop of quartzitic sandstones and blue limestones, dipping- 

 north 63^ west at an angle of 30°. Below these beds the red sandstones 

 outcrop at the point where the caiion begins at one of our sub-stations, 

 and between are limestones and limestone shales. 



The sub-station (a) is on a point opposite where the Bear bends from 

 its northern course to a northwest course. At this bend a stream comes 

 in from the north, occupying the axis of the anticUnal in which the Bear 

 hes to the south. The valley is continuous, and has beautiful meadows, 

 which have been only partially taken up by settlers. On the west side 

 of this valley is. a rather prominent riclge, on the south end of which 

 another sub-station (b) was located. This station is on red sandstones, 

 which dip south of east about 70°. Toward the north this dip must be 

 more to the south, as indicated by the dips observed farther down the 

 Bear on the west side of the antichnal. Still farther to the north the 



