PHYSIOGRAPHY OP THE PHILIPPINE ISLANDS: II. 23 



but with the abandonment of tribal warfare defense was no longer a 

 consideration and the sites were selected first, where gaps in the reefs 

 allowed water commnnication and second, with respect to the amount of 

 arable land ia the vicinity. 



The region around Santo Domingo owes its superior agricultural ad- 

 vantages to the piedmont deposit of gravel and fine volcanic material 

 from Mount Iraya. Eocks weather to form the same kind of soil in 

 the agglomerate regions of the island, but there the topography, marked 

 by a series of ridges and canons, makes conditions unfavorable. 



In this connection it may be well to note a point of danger to much 

 of the arable land of the Batanes. A large proportion of the cultivated 

 fields is upon steep hillsides, and the trees have been entirely cut away 

 from the ridges. The result is a gradual creeping down of the soil 

 toward the sea. In some pilaces this has gone so far that large cracks 

 have been formed, which follow the ridges for considerable distances. 

 Unless some reforesting is done along the tops of these ridges to hold the 

 soil, much valuable land will be lost. On the sides of the valley just north 

 of Santo Domingo, hedges around the fields seem to have held the soil 

 sufficiently to prevent cracks from forming. 



The natives of Batan and Sabtan owing to their isolation have become 

 a race of excellent seamen and boat builders, in comj)arison with the 

 slovenly seamenship and low constructive ability of the Ilocanos of 

 northern Luzon. Their small boats, or tatayas, built somewhat after 

 the fashion of a dory, are excellent surfboats and quick to answer the helm. 

 They make frequent trips to AjJarri in their large boats, built somewhat 

 like "a Chinese junk, and sometimes they even sail as far as Manila to sell 

 their hogs and cattle. These larger boats are built and owned by the 

 communities. A knowledge of the intricate tidal currents plays so great 

 a part in the life of the jDeople that the best pilots are the most important 

 men of the community. 



The natives of Isbayat, being more completely isolated through poorer 

 facilities for commimication, have retained more independent charac- 

 teristics, such as their own language and their peculiar art of basket 

 making. This island owing to its reputation for unliealthfulness, receives 

 no immigrants and is consequently underpopulated and largely given 

 over to pasture land. 



STJMMABT. 



In pre-Miocene times a land mass of considerable extent was built up 

 by enoi-mous explosive eruptions from unlmown sources and, after the 

 cessation of these explosions, was gradually worn down by streams to an 

 extremely mature topography. 



The next stage, from the Miocene to recent times, was one of predom- 

 inant uplift, limestone containing Miocene fossils being found at eleva- 

 tions up to 275 meters. This period was marked by renewed activity 



