392 cox. 



B. Deep seated igneous: 



Diabases, diorites, gabbros, granites, quartz porphyry (dike roek), peridotites, 

 pyroxenites, tonalite, and syenites. 



C. Volcanic : 



Andesites, basalts, rhyolites, daeites and trachytes. 



Some of these are merely enumerations, for no microscopic or special 

 study of them has been made. On the other hand it is probable that the 

 Icnown quantities are but a small proportion of those that actually exist 

 because of the meager exposures in the mountains and ravines, many 

 outcrops being entirely obliterated by covers of soil and heavy tropical 

 vegetation, and because certain districts have not yet been explored. 



It would be out of place here to discuss the distribution of these rocks. 

 However, it might be mentioned that the diorites and the andesites 

 of the second and third classes, respectively, are the most generally 

 distributed. The former occur very extensively in the Cordillera and 

 the latter in the Mariveles district, which forms the northern headland 

 of Manila Bay. The latter district is now being extensively mined by the 

 Atlantic, Gulf and Pacific Company for use in connection with the 

 sewer construction in Manila. 



Limestone occurs widely distributed practically throughout all the 

 Islands. 



Goodman ' reports limestone at Dmnalag and Pilar, Province of Capiz, "appear- 

 ing especially compact and seemingly fit for a building stone. In fact the church 

 at Dunialag, which was erected in 1873, as well as other buildings in the town 

 are constructed of this material. I noticed, however, that some of the blocks 

 in the church showed marked effects of weathering. Although fairly compact, 

 I do not believe that the Dumalag limestone is any more so than that which 

 may be quarried near Binangonan on Laguna de Bay, this latter having the 

 further advantage of being much nearer to Manila and to tide water." 



Mr. Goodman also reports with regard to tonalite that: "At the foot of Mount 

 Anjaoan, which is just off the main road and about a quarter of a mile southwest 

 of Colasi, is a massive outcrop of the tonalite which Abella reports as occurring 

 in this neighborhood. At Mount Deluca, a low hill about one hundred feet high 

 and about one and a quarter miles west of Anjaoan, the tonalite takes on a grayer 

 color, but in texture and mineral composition remains the same. The same rock 

 occurs again at Mount Jilonoc which is about the same height as Mount Deluca 

 and about one and a half miles west of it. Outcrops of tonalite are encountered 

 in various other places along the road between Colasi and the barrio of San 

 Fernando, and there in but little doubt that practically the same formation 

 continues for at least three miles east of Anjaoan. A thick growth of cogon 

 covers these hills so as to expose but comparatively small surfaces of the rock 

 in place, and these all appear massive, no systematic jointing being observable. 

 The stone is uniform and close grained, compact and hard, takes a good polish 

 and seems well adapted for use in heavy construction. It is well located too with 

 a view to quarrying and transportation. The harbor at Colasi, however, did not 

 strike me as nearly so perfect a one as I had expected and hoped to tind it." 



' An unpublished report made to the Chief of the Division of Mines, Bureau of 

 Science ( 1906), January. 



