10 



KOTO : XOTES OX THE GEOLOGY 



Banded fclsimr 

 sands and clays. 



No. 3. Basalt. 



Sandy c-lay with 

 lignite. 



Fi(.-. 3.— Section expcsed at the. west coast 

 of Jiii, Hôko. 



So. 1. Basalt. 



Basalt. 



Felspar sand witli 

 linionite r.olulcs. 



oartli, wholly consisting of the microscopic particles of plagio- 

 clase, a few fragments of pleochroic Jiypersthene, and little 

 magnetite, but no glass splinters are seen. It reminds me of 



the felspar sand that cover the 

 flat and form the ground of 

 Pampanga, north of Manila^\ 

 After this short digression, I re- 

 turn to the former subject. Xow, 

 a yellowish-brown, loose sandy 

 bed, -3 m. thick, comes below the 

 middle flow, locally with liraonitic 

 nodules (Fig. o) . This is succeed- 

 ed by another complex bed, 3 to 

 4 m. thick, made up of multi- 

 farious alternations of clays and 

 sands, all retaining the original 

 horizontal position. Then comes 

 the third sheet of porous lava 

 of variable thickness, underlaid by a lignite bed, the last one 

 can be only seen at low tide. The whole seems to me to be 

 one complex bed belonging to later Teritary ; and this profile 

 serves as a type of the stratigraphical order of the island. After 

 passing over the second ' haul-over ' to the Fûkibi point {Plate V), 

 opposite to Baku, nothing but the two upper flows is exposed. 



A table island, named Ko-sei-sliO"',off tlie coast of Jiri, 

 already referred to, is an erosion relic of the Basaltic mesa, 

 surely connected in former times with the main island of Hoko. 

 The adjoining wood- cut shows clearly the geological structure 



1) B. Koto, 'Geologic Strnctuie of the Malayan Arcliipehigo.' Tliis Jouinal, Vol. XI-, 

 p. 113. 



2) 



