NORTHWESTERN PANGASINAN. 273 
thickness of recent sedimentaries. These sedimentaries have not 
been metamorphosed nor intruded by dikes; they probably pos- 
sess little gold, but even on the assumption of its presence, ap- 
parently there have been no active waters to produce concen- 
tration into ore-bodies. 
Along the eastern and southern hills, igneous rocks make up 
the major part of the formation; hence, they can be considered 
favorable places for the occurrence of veins. Indeed, all veins 
within the region actually do occur within this igneous complex. 
North of Sual a quartz vein was noted on the Levant claim 
. | 
SAMPLING PLAN 
Marshall Workings 
140-141-142 
SHAFT Wo, 1. 
Fic. 3.—Sampling plan, Marshall workings. 
which appeared to be about 1 meter wide. The vein is poorly 
exposed, but seems to be of the fissure type. Some pyritization 
and silicification of the walls have taken place, but gold values 
appear to be absent. Assays of the vein showed 2 per cent 
copper. ' 
At Barlo on the Marshall group of claims, extensive silicifica- 
tion of the country rock has taken place. The formation is an- 
desite, and, by the action of siliceous waters circulating along 
fractures, considerable alteration of the rock has taken place. 
This silicified zone was mistaken by prospectors for an enor- 
