The first recorded indication of oil in a well in the Philippines was near Toledo, Cebu, in 1896 in highly folded and faulted lower Miocene sedimentary rocks. Since that time sporadic and unsuccessful efforts to discover commercial accumulations of oil have been made throughout the Philippines, both by local groups and by the major international companies. Quite naturally a significant part of this effort has been concentrated in Cebu, although most deep drilling by major operators has been in Luzon and especially in the Cagayan basin in the north of that island.

Hydrocarbons are present in the Miocene strata of southwestern Cebu, and the complete dependence of the Philippines on imported supplies should make development on a relatively small scale commercially attractive. Such development has been impeded by the confusion of the stratigraphic conditions in the area, and it is hoped that the basic geologic reasoning presented here will help to resolve this. Any development of hydrocarbon production in southwestern Cebu should lend impetus to the exploration of the rest of the archipelago including the offshore areas.