23,5 Dicker son: Baguio Plateau 423 



About 100 meters south of the fossil locality 40x, Mr. Graham 

 B. Moody and Dr. W. D. Smith found andesite in a creek bank, 

 elevation 900 meters (3,000 feet, aneroid). Mr. Moody stated 

 that the andesite was in place and was probably instrusive in 

 the Vigo. Since a residual of Malumbang limestone occurs at 

 1,065 meters (3,550 feet, aneroid) and possibly rests upon the 

 andesitic dike, it seems quite probable that the andesite is of 

 post- Vigo and pre-Malumbang age. Doctor Smith has kindly 

 examined a thin section of this rock and described it as follows : 



This is a badly weathered andesite consisting largely of glassy feldspars, 

 sanidine, in a glassy groundmass in which one sees grains of magnetite, 

 flakes of some ferromagnesian minerals, either pyroxene or hornblende. 

 The feldspars even in the fresher-looking portions are somewhat decom- 

 posed, while in the outside portions of the specimen they are completely 

 kaolinized, giving a whitish appearance to the rock. This rock would 

 be classed in the older terminology as trachyte. 



About one kilometer east of locality 40x, at a coal prospect 

 made by Governor Whitmarsh's men, a black lignitic sand- 

 stone and a black lignitic shale with a strike of north 30° west 

 and a dip of 40° west were noted. The intervening area was 

 evidently sandstone and shale of the Vigo group. 



In a creek at an elevation of 1,086 meters (3,620 feet, ane- 

 roid), 1.5 kilometers east of locality 40x, dark lignitic sand- 

 stone occurs in fault contact with a coarse conglomerate whose 

 bowlders are composed of diorite and andesite. Thirty meters 

 (100 feet) below, Mr. Moody obtained a dip of 30° south. 

 Governor Whitmarsh found a large specimen of Vicarya callosa 

 here, but when we visited the locality no fossils were obtained. 



VIGO FAUNA 

 Another very interesting locality was discovered by Mr. James 

 Wright, superintendent of the Trinidad Agricultural School, 

 and Mr. Charles Mitchek, the foreman in charge of the stock 

 farm. This locality is 200 meters north of the stock-farm 

 buildings and was uncovered while they were attempting to 

 develop water by an open cut in a small creek. The strata 

 exposed in the small creek consist of coarse arkosic sandstone 

 which in places is decidedly argillaceous. The structure in this 

 vicinity is highly complicated by faulting. The strike is prac- 

 tically due north and south with a dip of 20° west. In the 

 hills 0.8 kilometer east of this point, this arkosic sandstone is 

 interbedded with tan tuffaceous marl exactly like the marl ex- 

 posed in the intersection of the Naguilian and Campo Filipino 

 Roads. 



