2 . FERGUSON. 



Physiogeaphy. 



Formation of the land. 



The Sabtan Upland. 



Period of Uplift and Erosion. 



Sinking of Ibujos and Desquey. 



Possible Recent Depression. 



Marine Erosion. 



Tidal scour. 



Coral. 



Vuleanism. 



Human response and physiographic conditions. 



Summary. 



INTHODUCTION. 



This paper, embodying results of worlc during three weeks spent in 

 geologic reconnaissance in the Batanes Islands, is intended to be pre- 

 liminary to an article which will deal more fully with the geology and 

 petrography of this group ; hence the problems of structural geology will 

 be in the main reserved for the later discussion and I shall here confine 

 myself principally to the physiography. 



Before proceeding to a description of this group, I wish to acknowledge 

 my indebtedness to Major-General Leonard Wood, commanding general, 

 Philippines Division, to Commissioner Dean C. Worcester, to Mr. William 

 Edmonds, supervising teacher of the Batanes Islands, for his unfailing 

 hospitality and for much helpful information, and to the native teachers 

 and boys of his schools, particularly Mr. Jose Aguedo, for their freely 

 rendered services as guides during my stay in the islands. 



LOCATION. 



The Batanes Islands form the most northern portion of Philippine 

 territory and consist of the islands of Y'Ami, Maysanga," Mabudis, 

 Siayan, Isbayat, Inem, Batan, Sabtan, Iljujos and Desquey, of which 

 Isbayat, Batan, Sabtan and Ilmjos are inhabited. They lie between lati- 

 tude 30° 16' and 21° 0.5' north (31° 13' north if the "existence doubifid" 

 Bashi rocks are included), or approximately the latitude of the southern 

 half of the Hawaiian Islands, and between longitude 131° 49' and 122° 

 08' east. Y'Ami, the most northern island, is about 370 kilometers from 

 Cape Engaiio, the nearest point of Luzon, 107 kilometers from the Ja- 

 panese island of Little Botel Tobago and 160 kilometers from the southern 

 point of Formosa. It is said tliat on a very clear day the Formosan uKJun- 

 tains can be seen from the summit of Mount Iraya in Batan Island. The 

 Bashi Channel with a minimum depth of 1,009 fathoms separates the 

 islands from Formosa and the Botel Toijagos to the north, while on the 



^ Where the local name diflers from that given on the United States Coast 

 and Geodetic Survey chart, I have followed the local usage. This chart, based 

 on a British survey made in 1845, is badly confused as to local names, and is 

 unreliable in regard to details of topography. On the maps reproduced in this 

 paper the names are corrected to conform to local usage. 



