The regional geological study of the Philippines has been almost continually going on since F. G. Becker published the first account on the geology of the Philippines in 1899. Notable contributions have been made by W. D. Smith, 1907-1924, Faustino, 1920-1927, Abadilla and Alvir, 1937-1941, G. W. Corby, 1939-1940, E. Irving, 1946-1956, J. Teves, 1937-1958 and L. Santos-Ynigo, 1946-1960. The Geological Survey and Petroleum Divisions of the Philippine Bureau of Mines have in recent years covered considerable areas and private petroleum companies have worked many sedimentary basins, but relatively few reports on those have been published. Nevertheless, the Geological Survey Division and the National Committee for the Preparation of Geologic and Tectonic Maps formed in 1962, have compiled most of these data which were incorporated in the recently published Geologic Map of the Philippines in scale of 1:1,000,000.

The summarized data as of 1963, together with the study of geological structures, was reported by the author in the XXII International Geological Congress (New Delhi, India, 1964) in a paper entitled “Notes on the Tectonic Study of the Philippine Archipelago". A generalized summary of updated data which includes new findings made since 1963 by the Geological Survey, is shown in Table I. The writer refers to the above cited published work for more detailed information on geological findings, especially the distribution of various rock units, their structures and nature of deformation.