GEOLOGICAL RECONNAISSANCE OP LEYTE. 353 



a ^erv shallow jDort and ships must anchor well out in the bay. At low 

 tide a broad beach is left bare, and the channel across it is too shallow 

 for transporting cargo by lighters. On the east coast the towns are un- 

 protected ports and open toward the Pacific. As a result, Tacloban, 

 which has deep water and is well protected, will always receive a large 

 amount of traffic from the plains district. 



Geologic formation. — With the exception of a few exposures in low 

 river banlvS which reveal very soft sandstones and poorly cemented con- 

 glomerates, little idea of the underlying formation of the northeastern 

 plains can he obtained. Its surface deposits are largely alluvial and have 

 been brought down by the streams from the Cordillera. Accordingly, 

 near the foot of the Cordillera, coarser sediments are to be expected, and 

 along the sea coast where the plains are low, little else is seen besides 

 beacli sand and silts deposited near river mouths. Eeference has already 

 been made to the partially buried hills, which are the southern continua- 

 tion of tlie northeastern semi-mountainous district. The occurrence of 

 some low hills near Alangalang which are probably .outliers of the Cor- 

 dillera district, has been noted in connection with the descri|)tion of the 

 Cordillera. Also reference has been made to the hills which surround 

 Lake Bito. These are all inliers in the plain and give very little informa- 

 tion as to the general formation. The only place thus far at which 

 a deep well has been drilled in this district is Carigara, where artesian 

 water was encountered at a depth of 56 meters. An examination of the 

 samples of drillings which came from the well showed sands, detrital 

 material from andesite rocks such as might have Ijeen brought in by rivers 

 from the Cordillera, and interbedded marine sands containing marine 

 shells. While it is not possible from the present data to prove the emer- 

 gence of 'this plains district, it appears very reasonable to suppose that it 

 was a strait at some period not very far removed, and that the elevation of 

 the island has converted it into an alluvial plain, the surface of which 

 has been aggraded by the streams. Marine sediments may be expected 

 under the alluvial surface deposits. 



GEOLOGIC HISTOEY. 



Our present knowledge of the geology of Leyte is very incompilete but 

 it |)oints to an interesting history of the island which may be tentatively 

 outlined as follows : 



The basal formations do not appear in any area thus far studied 

 unless the dioritic rocks represent the igneous portion of the older forma- 

 tions. Thus far diorites have been found only near Malitbog, and, pos- 

 sibly, as Becker has suggested, they are represented at the gold mines on 

 Panaon Island. 



In the northeastern district there is a series of sedimentaries, perhaps 



