PE^i^j GEOLOGY SECTION NO. 19. 235 



Section G. 



1. Volcanic, capping the bill. 



2. Black limestoue, very much metamorphosed. 



3. Yellow quartzite. 



4. Volcanic, in columns. 



5. Quartzite. 



6. Volcanic. 



7. Quartzite. 



8. Volcanic. 



9. Quartzite. 

 10. Gneiss. 



In these three sections just given the bed marked No. 1 is the same in 

 all. So is the bed of limestone marked No. 2 in all the sections. No, 3 of 

 the second section, (&,) in the third (c) has been split up into four beds, 

 Nos. 3, 5, 7, and 9. In the lirst, (a,) it has been split into six beds, viz, 

 3, 5, 7, 9, 10, and 12. 



No. 4 of section (&) which is represented in the first {a) by Nos. 4, 6, 

 8, and 11. In the third section (c) the volcanic rock is much thicker, 

 and is represented by Nos. 4, 6, and 8. It has thrown the fragments of 

 quartzite, Nos. 5, 7, and 9, lower down. The bed, No. 10, corresponds 

 with No. 5 of the second section. The hill marked G in the illustration 

 (Fig. 2, Plate IX) is capped with volcanic, and below are sedimentary 

 beds again which have dropped down. The center is gueissic. Still 

 farther down the creek, at the point D, is another fault, and then a fold 

 which is merely local in the quartzite between a and h. At the latter 

 place there is a break again, and then the quartzites are almost, if not 

 quite, horizontal. At E is another fault, and beyond the quartzites dip 

 about 12°. It will be seen that in all these faults the down- throw is on 

 the west side. In California Gulch, which is the one next north of Iowa, 

 the rocks are more covered up, but there is probably the same condition 

 of affairs as we see here. We have seen, then, that there are two ma4n 

 lines of faulting running north and south, which we have traced from 

 Mount Lincoln southward to Horseshoe Mountain, a distance of about 

 ten or eleven miles. In Plate XII is represented a section made 

 through stations 56 and 57, about five miles south of Four-Mile Greek. 

 The section is as follows : 



Section No. 19, made hy Mr. Gardner. 



a. 1. Gonglomerate. 



2. Soft white limestone. 



3. Gray limestone. 



4. Nodular limestone. 



5. Blue limestone. 

 G. Quartzite, white. 



6. 7. Schists with veins of granite. 



8. Quartzite. 



9. Nodular limestone and shales. 

 10. White quartzite. 



c. 11. Gneiss and schists. 



12. Limestones. 



13. Quartzite. 



d. 14. Gneiss. 



The faulting in the center of the diagram is evidently the second or 

 western fault at Horseshoe. That is the one observed on the divide. 



