298 



S. PAIGE ORIGIN OF THE HOMESTAKE ORE BODY 



open cut, though the stratigraphic distance between them seemed at this 

 place to be less than 350 feet. Surface oxidation of the pyritized beds in 

 which this cut is opened, of course, gives a different appearance to the 

 conglomerates, yet their dominant characteristics — quartzitic nature and 

 flattened pebbles — can be recognized. To the southwest these beds (the 

 'upper" conglomerate) may again be observed on the eastern rim of the 

 great Homestake open cut and may be traced down this rim to the ma- 

 chine shops on the edge of the town of Lead. If the stratigraphy, which 

 has been barely outlined above, proves correct, it is obvious that the 



lectio r\ 



A 

 / \ 



/ \ 



/ 



/ A V 



//AV 



filial 



Figure 2. — Diagrammatic Plan and Cross-section 



"lower" conglomerate must lie near or just below the bottom of the great 

 open cut and the ore body would then coincide with the limestone. A 

 synclinal trough of ore exposed in the De Smet cut is particularly inter- 

 esting from a structural standpoint. It is suggested that this particular 

 synclinal fold is but a minor one imposed on the western limb of the 

 larger anticlinal referred to above. It pitches southward and the outcrop 

 of its eastern limb should theoretically be traceable on the surface were 

 it not interrupted by porphyry intrusives. It is believed at present that 

 the fault cuts this fold and the larger anticlinal somewhat as illustrated 

 in the purely diagrammatic figures on page 298. 



Such an interpretation accounts for all the facts at present known. 



