PHYSIOGRAPHY OF THE PHILIPPINE ISLANDS : II. 11 



Inem Island, north of Batan, is noted on the chart as "volcanic" and 

 the height is put at over 1,800 feet (550 meters). These two facts 

 represent practically all the information I have been able to obtain con- 

 cerning this rock. It is a lone rock rising out of the sea, with steep cliffs 

 on every side, and dangerous currents make landing there practically im- 

 possible. As seen from the deck of the steamer it is an extinct volcano 

 which has suffered heavily from marine erosion. Eef)orts are current 

 that steam has been observed to rise from its summ.it, but I am inclined 

 to believe that the small clouds which often hang around the mountain 

 are responsible for this belief. 



THE SIATANES. 



The islands lying north of Isbayat are locally grouped together as the 

 Siayanes, a word said to mean "good tishing grounds." However, the 

 natives seldom venture north of Isbayat, as there is a strong northerly 

 current which has more than once carried their boats to the Japanese 

 island of Botel Tobago where they have suffered from the attacks of 

 savages." The islands of Siayan and Mabudis of the Siayanes Group, 

 judging from what could be seen from the steamer, seem to be composed 

 of lava flows with a small amount of limestone. Mabudis shows a sharp, 

 irregular peak, possibly an extinct volcano above a fairly level terrace. 

 (See PI. VIII.) Both of these islands are largely cliff -bound and have 

 probably been separated by marine erosion. North of these is another 

 pair, Y'Ami and May sanga (or North Island). Y'Ami, on which I was 

 able to land for a short time, is a small island of considerable height 

 and, except for a few feet of coral near the shore is composed entirely of 

 volcanic material. There is a considerable quantity of stratified and 

 cross-bedded sandstone in the lower part, above this a volcanic agglom- 

 erate, consisting of basalt fragments and bombs. Interbedded with this 

 are several flows of basalt., I did not have time to reach the top of 

 the island and so could not determine whether or not it was a volcano, but 

 from the apparent horizontality of the lava flows I did not consider it 

 probable. The same flows seem to be continued on the neighboring 

 island of May sanga, which is probably separated from Y'Ami by marine 

 erosion. It seems likely that all four of the Siayanes islands, together 

 with their outlying rocks and perhaps Inem and Batan, once formed a 

 single land mass, built up by flows from Mabudis, or perhaps from Inem 

 or even Iraya. 



"Davidson, J. W. : Formosa, Past and Present (1903) mentions "Bashe" Is- 

 landers as being shipwrecked on Formosa and the Batanes people are now living 

 on Botel Tobago. 



