442 SMITH AND EDDINGFIELD. 



small amount of gold in the veins. There is reason to believe, also, 

 that in certain parts of the Bengnet region there is a great deal of 

 chlorine present in the underground water because of the salt springs 

 which exist there. Xote, for instance, the amount of sodium chloride 

 in the analysis of the Klondike Spiing, on page 439. 



We can feel sure then, that we have the proper conditions for the 

 reactions outlined above. 



The above discussion in so far as it relates to the Benguet regions, 

 can be summed up in the following conclusion: 



We can reasonably expect to find the gold values increasing with 

 depth in the veins carrying manganese, though exceptions to this are 

 known. (W. D. S.) 



OXIDIZED AND SULPHIDE ZONES. 



Inasmuch as no mine in Benguet as yet has gone below the zone 

 of enrichment, what will be found in the sulphide zone can not be 

 foretold. Some of the prospects are at present in tlie semi-leached 

 zones and some in the zone of enrichment. In both the?e cases the 

 ore appears to be veiT good, but no information is available as to its 

 condition in depth. In one case, a vein, strong on the si;rface, pinched 

 out almost comj^letely within a deptli of .30 meters. In another, the 

 good values seemed to lead in depth into the adjoining property, yet 

 on the other hand, the Muj'ot has been developed to a depth of over 

 100 meters below the highest point in the outcrop and appears to be 

 as strong below as it was near the surface. It is opened by adits only, 

 so that it- scarcely can be taken as an example of ore at depth, although 

 the ore generally seems to be primary. Another case is supplied by 

 an ore vein in Emerald Creek. At tlie highest exposed point the vein 

 is only 1 meter wide, but 33 meters lower and about 1 kilometer 

 distant, it has reached a width reported to be over 13 meters, still in 

 a wholly oxidized, semi-leached condition. These conditions point to 

 ore bodies in depth, but they may or may not be rich enough to work. 

 Telluride ore has been found by one prospector, which although formerly 

 accepted as pointing to ore in depth, might be secondary in its formation. 

 Generally the values in the veins are greatest next to, one or both of 

 tlie walls; and in the majority of cases it is apparent that this charac- 

 teristic is due to secondary enrichment by descending waters. (F. T. E.) 



ECOISrOMIC GEOLOGY. 



In the bulletin, !Mineial Resources of the Philippines, will be found 

 each year a statement of the gold production of this district, with 

 more or less discussion about eneh property, and in the 1912 bulletin 

 a fairly complete description of them will appear. Suffice it to say 

 in this place that there are about 2.5 gold properties; on four of them mills 

 are now running or have been until recently. 



