220 



The Philippine Journal of Science 

 Well No. 308, Janiuay, Iloilo. 



1915 



I Depth in 

 ' meter*. 



0- 6 



5- 10 



10- 15 



15- 20 

 20- 36 



35- 37 

 37- 41 

 41- 43 

 48- 65 



55-124 

 124-147 



147-169 

 169-175 

 175-187 

 187-199 



199-207 



207-247 

 247-266 

 266-273 

 273-315 

 315-320 

 320-348 

 348-360 

 360-428 

 428-468 

 468-490 

 490-493 

 493-506 

 506-527 

 527-531 

 531-537 



StraU. 



Drillers' claBBification. 



Gravel and clay 



Bowlders and clay 



Gumbo clay 



Black sticky clay 



Joint clay 



Blue sticky clay i 



Blue sandy clay and sravel i 



Clay and gravel 



Blue sandy clay and joint clay 



Joint clay 



Clay and loose stone 



Joint clay 



Joint clay and loose stone 



Joint clay 



Volcanic 



Quick clay 



Joint clay and loose stone 



Joint clay 



Joint clay and loose stone 



Joint clay 



Joint clay and loose stone 



Fine sand and gravel. 



Joint clay and loose stone 



Joint clay 



Brown sand and clay 



Joint clay 



Shale 



Rock 



Clay bowlders and quicksand 



Shale mixed with fine black sand 



Sand, gas, and salt water 



BemarkB. 



Gumbo clay is probably a stitT dark-colored 

 clay. 



Joint clay is applied to the blue clay of the 

 upper clay and shale series of this record. 



Alluvial to 4!] meters. Upper clay and shale 

 below 55 meters. 



"Loose stone" is probably applied to calcareous 

 concretions which are known to occur in the 

 blue clay. 



"Volcanic"— possibly a silt which was mistaken 

 for volcanic tuff. The drill penetrated it 12 

 meters in 9 hours. 



Rock, calcareous shale. 



Clay bowlders. 



Sand from strata above mixed with shale. 



sediments, cross-bedding, and other factors all indicate that there 

 were either repeated oscillations of level or rapidly succeeding 

 freshets, or both. It is important to note that the conditions 

 are unfavorable for the formation of coal deposits of economic 

 size. The only coal seams seen by me were not over 5 centi- 

 meters thick. 



STRUCTURE 



The Tertiary series of shales and sandstones described above 

 overlap the igneous core of the cordillera and constitute a great 

 monocline dipping eastward toward the Iloilo plain. Near the 



