282 The Philippine Journal of Science vm 



Cenosphsera affinis Hinde. Plate XX, figs. 1 and 2. 



Hinde, Descript. Foss. Radiolaria from rocks of central Borneo, ap- 

 pendix I in Molengraaff's Borneo (1899), PL I, fig. 7. 



These 2 figures are photomicrographs of a section of an old 

 slate from Bulacan Province found in 1912. by. F. A. Dalburg. 

 They show many individual Radiolaria, but only 2 or 3 specimens 

 which can be plainly identified. The spherical form I have 

 referred .to C. , affinis. The magnifications in the two figures 

 are 100 and 200 diameters, respectively. In this specimen we 

 find only the structure of the shell, the interior being completely 

 taken up with a filling of cryptocrystalline silica. 



DICTYOMITRA Zittel 



The latticed test is conical or cylindrical without horn, and 

 with an open basal aperture. The constrictions are horizontal. 

 (Hinde.) 



Dictyomitra tenuis Hinde. Plate XX, figs. 1 and 2. 



Foss. Radiolaria from Central Borneo (1899), PI. IV, fig. 15. 



The oval-shaped section in these figures is thought to be a 

 section of a form belonging to this species. These forms are 

 all so generally devoid of any special character that there is 

 reason for some latitude in their determination. 



In Plate XII, fig. 1, is shown a section of a jasper from Ilocos 

 Norte, Luzon, collected by me in 1906. I called attention to the 

 resemblance of this specimen to the radiolarian cherts of Cali- 

 fornia. 27 Since that time I have learned both from conversations 

 with Dr. K. Martin in Leiden and from recent literature that 

 similar jaspers and cherts have been found in Borneo, Java, and 

 the Moluccas 28 and that they are there referred provisionally to 

 the Jurassic. 



In the Ilocos Norte jasper no distinct radiolarian characters 

 could be made out, only small roundish areas filled with crypto- 

 crystalline silica were visible. 



Similar ancient-looking rocks have been found on Panay, on 

 Balabac, and in Pangasinan Province, Luzon, but sections of 

 the rocks collected by Dalburg in the Eastern Cordillera of 

 Luzon were the first to show any determinable specimens. 



."This Journal, Sec. A (1907), 2, 158. 



88 Martin, Reisen in den Molukken. Leiden (1903), Geolog. Theil, PL VI, 

 fig. 5. 



