vra, a, 4 Smith: Fossil Invertebrate Fauna 247 



northern Mindanao, in Surigao Peninsula particularly, there is a 

 metamorphic area consisting of argillo-arenaceous and micaceous 

 schists with quartz stringers. These may possibly be older than 

 the Tertiary, but there is no fossil evidence nor has any 

 satisfactory field evidence been brought forward to show that 

 they lie below the Tertiary series, although similar schists 

 are found in that position in Java. We may yet find the same 

 to be the case here. 



Distribution. — The general statement may be made that the 

 oldest rocks probably are those found in the deep canons of 

 the Cordilleras of Luzon. In many other parts of the Islands 

 where we might hope to find them we encounter everything 

 covered by a sheet of volcanic rocks, as is the case with much 

 of the western part of Mindanao, or else by a mantle of coral 

 limestone, as in Cebu. Flanking these older rocks, and dipping 

 away from them both to the east and west, are the Tertiary 

 sediments, limestone, sandstone, shale, and the intercalated coal 

 seams; above these are andesites and basaltic flows, while the 

 youngest consolidated formation of all is the tuff of the vicinity 

 of Manila. It is not easy in our present state of knowledge to 

 delimit all of these formations; indeed, many which appear to 

 be of different age are, in reality, contemporaneous. Another 

 noteworthy fact is particularly well exemplified in Cebu, namely, 

 that there is no apparent break in the limestone from the coral 

 reef on the shore to the capping of the cordillera in the center of 

 the island, at a height of 1,000 meters. It probably sank below sea 

 level and subsequently rose so gradually that the whole island was 

 covered with a mantle of coral. This mantle has since largely 

 been removed by erosion. The map (Plate I), showing the 

 general distribution of the various formations throughout the 

 Archipelago, was prepared in this Bureau from data from 

 various sources, but mainly from our own surveys. 



COMPARISON WITH JAVA 



Martin 18 in his paper concerning Tertiary fossils in the Philip- 

 pines which was translated by Becker as a complement to his 

 report on the geology of the Philippines, called attention to the 

 strong resemblance of the fauna of the Philippines to that of Java 

 based on his examination of the Semper collection now in the 

 Reichs-museum in Leiden. The Semper collection contains the 

 following fossils already determined : 



" Samm. d. geol. Reichs-mns. in Leiden (1896), 5, 53-69. 



118366 — 4 



