REPORT ON THE PETROLOGY OF OCEANIC ISLANDS. 



161 



towards the Moluccas, dividing there into two branches, one of which trends towards 

 Java while the other stretches eastward to meet New Zealand. 1 



Several of the Philippine Islands have lately been the subject of important geological 

 observations, and to these we shall have occasion to recur. Professor Roth has given 

 an account of the geology of the archipelago in an Appendix to the narrative of the 

 explorer Jagor. 2 This work exemplifies the great erudition and precise knowledge 

 which distinguish this geologist. I wish to mention very specially the results obtained 

 by Von Drasche during his scientific voyage among the Philippines ; 3 and, finally, the 



New Volcano, Camiguin Island. 



excellent monograph, published by Professor Oebbeke, on the rock specimens collected 

 on these islands by Professor Semper. 4 In spite of the peculiar interest which ought 



1 In considering in more detail the relations of the Philippine archipelago to the neighbouring lands, it can be 

 connected with a chain of islands which commences at Formosa, passes through the somewhat scattered groups of the 

 Batan and Babuyan Islauds, and runs on to Luzon. At this point the great chain breaks up into a series of secondary- 

 chains, which lead to the Sunda Islands. The group of Busuanga and the island of Palawan trend towards the north 

 point of Borneo ; the western portion of the peninsula of Mindanao and the Sulu Islands seem to link themselves 

 to the north-east end of Borneo ; Luzon, Samar, and Mindanao lie on a curve, the convexity of which is towards the 

 Pacific Ocean. To the south of Mindanao comes the chain of the Sangir Islands, which advances towards the Celebes 

 and the Talant Islands. These latter stretch towards Halmahera. See F. S. Hahn, Insel Studien, p. 49, Leipzig 1883. 



2 Fr. Jagor, Reisen in den Philippines Berlin 1873 ; appendix, p. 333 : Ueber die geologische Beschaffenheit der 

 Philippinen. In this notice by Professor Roth are condensed all the observations on the geology of this archipelago 

 which had appeared before the publication of Jagor's book ; it contains, besides, a large number of personal observations 

 on the lithology and mineralogy of these islands. 



3 R. von Drasche, Fragmente zu einer Geologie der Insel Luzon, Wien, 1878. 



4 K. Oebekke, Beitrage zur Petrographie der Philippinen und der Palau-Inseln, Stuttgart, 1881. 



(PHYS. CHEM. CHALL. EXP. PART VII. — 1889.) 21 



