viii, a, 4 Smith: Fossil Invertebrate Fauna 239 



Lagendae, Nodosaridse, Glandulinidas, Frondicularidse, Pleurosto- 

 mellidae, Cristellaridse, Polymorphinidse, Textularidse, Globigeri- 

 nidse, Rotidae, and Polystomellidae. It can be seen from this then 

 that minute forms like these are abundant. Similar shales in 

 Cebu and on Batan Island are likewise rich in Foraminifera. 



Limestones. — These are for the most part coralline or foram- 

 iniferal. They are very pure chemically, the magnesia content 

 being generally less than 2 per cent. On Guimaras Island a 

 slightly higher percentage has been noted in some samples. 

 They vary in color from cream-white through buff to black. 

 They have an extensive development, and vary in age from 

 Oligocene to Recent. 



The recently elevated limestones which are very widely dis- 

 tributed in the Philippines are for the most part simply raised 

 coral reefs being largely composed of triturated and recemented 

 coral fragments, although in places the reef has been little 

 disturbed. Great masses of astreas, helioporas, meandrinas, 

 turbinarias, etc., intact in the center of a mass of indurated 

 limestone, are very common. These reefs occur at various eleva- 

 tions from sea level to more than 2,000 meters. The raised 

 reefs have very much in common with those in many parts of 

 the Pacific Ocean and China Sea region." The best development 

 of these raised reefs is along much of the Cebu coast, the coast of 

 Ilocos Norte, in the limestone just west and north of Baguio in 

 central Luzon, and near the north coast of Mindanao. 



Becker long ago called attention to the mantle of coral lime- 

 stone which must have entirely covered Cebu Island at some 

 past time. It is possible for one to walk from the living reef 

 fringing the shore to the highest pinnacle of the island in the 

 Central Cordillera and, except for occasional short breaks where 

 some stream has cut down through the mantle, to keep always 

 on the limestone. This means that there is apparently no break 

 between the present and the Pliocene. But this is what one 

 would expect. 



Other phases of the limestone are frequently encountered as 

 a recemented rubble formation, well shown in the lower narrows 

 of Danao River in Cebu. 



• On this subject the following papers should be consulted : Newton, R. 

 B., and Holland R., On some fossils from the Islands of Formosa and Riu- 

 Kiu, Journ. Coll. Sci., Imp. Univ. Tokyo (1902), 17, art. 6; Chapman, F., 

 On the tertiary limestones and foraminiferal tuffs of Molekulas, New 

 Hebrides, Proc. Linn. Soc. N. S. W. (1907), 32, pt. 4; Becker, G. F., 21st 

 Ann. Rep. U. S. Geol. Surv., Washington (1901), pt. 3. 



