GEOLOGIC RECONNAISSANCE OF SOUTHWESTERN LUZON. 107 



distance of a long day's march in the rugged and very little known 

 country to the northeast. 



Iron deposits near Santa Inez. — A deposit of iron which has never 

 been worked occurs a short distance to the north of Santa Maria, in the 

 valley of the Santa Maria Eiver which enters the northeast arm of Bay 

 Lake. The position of this deposit is shown on d' Almonte's map of 

 Luzon, and to the south of it there is indicated an outcrop of coal. From 

 inquiry it was learned that neither the coal nor the iron are of sufficient 

 importance to warrant special investigation. 



COPPER. 



Prospects in the Loboo Mountains. — Some prespecting for copper was 

 carried on in the northeast part of the Loboo Mountains on the head 

 waters of the Calbasahan Eiver. The locality was visited by Smith in 

 1905. He described the occurrence of fissure veins which are in two 

 sets, the main ones striking in a direction north 70° west, and the others 

 north 45° to 57° west. The country rock is a diorite with more or less 

 gneissic phases. The principal copper ores found were black oxide of 

 copper and bomite with some carbonates, but oceuring in small pockets 

 and thin veins. Inasmuch as the prospecting did not develop any work- 

 able deposits, they were abandoned. 



Prospects on the Lanatin River. — In describing the iron deposits on 

 the Lanatin Eiver, reference has already been made to the occurrence of 

 copper stains on the iron ores, and occasional small pockets of copper 

 ores. The prospecting failed to show an encouraging amount of ore. 



GOLD. 



Many reports have been received concerning the presence of placer 

 gold in the rivers which have their sources in the eastern cordillera to 

 the north of Bay Lake and in places some platinum is found with the , 

 gold. For example, the Mariquina Eiver near Manila carries a little 

 fine gold, and prospectors have panned a good number of colors in the 

 Novaliehes Eiver and in streams further to the north. There is little 

 reason to suppose that any of these placer deposits, even if locally work- 

 able, will prove important. They have been investigated many times. 



Just to the north of San Isidro on the trail to Santa Inez, there are 

 a number of pits dug near the trail in an area of low land bordering a 

 small stream. This locality has been prospected within' the last few 

 years and some gold found, but not enough to warrant systematic work. 

 San Isidro is now within the watershed of Manila water supply reserva- 

 tion and further work at the locality is prohibited. However, there is 

 little reason to believe that anyone would care to make further attempts 

 at the place. The following explanation of the occurrence of placer 

 gold at the localities described above is offered with some hesitancy. 

 It has been shown, in discussing the geology of the eastern cordillera, 



