56 GEOLOGICAL RECONNOISSANCE 



it is true, contains a higher percentage of metal than the carbonate; but it 

 is much more difficult and expensive to work, and hence a less profitable 

 ore to mine than the carbonates, with a less per centage of zinc in their 

 composition. 



The higher points of the hills in this part of Marion county, are capped 

 with eherty rocks of subcarboniferous date, but the lower part of the hills 

 belongs to the same age as the members exhibited in the geological section 

 on Sugar-loaf creek, previously given. 



The pine and other timber on the high ridge, mentioned as intervening 

 between the head of Sugar-loaf creek and the waters of George's creek, 

 will afford good coaling grounds for the use of zinc furnaces, which might 

 be located some where in the vicinity of these zinc mines, as well as for 

 the reduction of the lead ore that may be raised towards the head of 

 Sugar-loaf creek. 



CARROLL COUNTY. 



As yet, only the eastern portion of this county has been examined. 

 The lead ore of this county, occurs in the cotemporaneous formations of 

 magnesian limestones, with occasional interstratification of sandstone and 

 siliceous limestones, overlaid, towards the summits of the hills, by the en- 

 crinital limestones and marble rock, capped with chert. The diggings 

 have been somewhat deeper in Carroll than in Marion county, but still 

 quite limited, consisting of a few shallow trenches on the hill-side, and 

 one shaft of 40 feet. These have exposed several lead-bearing crevices in 

 the rocks, sometimes expanded into cavernous spaces forming occasional 

 " pockets" filled with lead ore; at other times compressed in the joints of 

 of the wall-rock, almost in contact, or only affording space enough for 

 small " strings," and thin " sheets" of ore, irregularly distributed along its 

 course. 



In sinking the main shaft, the first layer of rock passed through, beneath 

 the subsoil and under-clay, was: 



Light grey shale 4 feet 



Dark " " 8 " 



Magnesian lead-bearing limestone 28 " 



Total depth sunk 40 " 



A hole carried a few feet further, by means of a " churn auger," passed 

 mostly through good solid galena disseminated in the adjacent magnesian 

 limestone. 



