18 PROCEEDINGS OF THE NATIONAL MUSEUM vol.74 



ous small brilliant yellow crystals of apatite, apparently contempo- 

 raneous with the martite. An analysis of this ore yielded the fol- 

 lowing results : 



Iron Ore, Plcacho <S'oeffro» '/ 



Forest A. Gonyer, analyst 



0.52 



.48 



SiO. 



l^O. ] 



re.O= S6.60 



AI.O3 1.76 



FoO 4.S8 



CaO 2.56 



MffO 0. 20 



MnO xone. 



P2OJ None. 



n.o . 10 



100. 01 



Later examination of the specimen analyzed showed it to be ab- 

 normally rich in apatite and accounts for the high phosphate value. 

 The iron content calculated to metallic iron is 64.41 per cent. 



From Picacho Socavon 2, the ore is less crystalline and more com- 

 pact. Here it is massive, with only a few small vugs, is dark steel 

 gray to brilliant iron black in color and is hard and tough. Except 

 for small druses and thin seams of quartz no other mineral was noted 

 except that on polished surface the small vugs are seen to be lined 

 with a thin coating or goethite and a few small patches, apparently 

 former cavities, are now completely filled with that mineral. An 

 analysis of this ore gave the following : 



Iron Ore, Picacho Socavon 2 

 Forest A. Gonyer, analyst 



SiO. 944 



TiO. N„ne. 



Fe.03 85. 40 



AI.O3 4 12 



FeO ~; .58 



CaO .08 



MgO 0. 20 



MnO No„e. 



P.O. None. 



H.0 .19 



100.01 



Besides the ores now being mined the so-called holeo ore flanking 

 the hill on several sides was of importance in the early days of smelt*^ 

 ing. This ore consists of pebbles and bowlders of detrital ore, in 

 some places loosely cemented, in others loose and gravelly. It con- 

 sists largely of hematite in the form of pebbles or as loose martite 

 crystals, often superficially converted to limonite or coated and ce- 

 mented by the latter mineral. Because of its lower phosphorus con- 

 lent, this ore is said to be very high grade and is therefore particu- 

 larly desirable. 



ORE BODIES 



There are four main masses of iron ore at Cerro Mercado. The 

 one now being actively worked flanks the hill on the west, forming 

 a prominent ridge and has a length of 800 meters and a maximum 



