314 The Philippine Journal of Science wis 



Schlumberger (Oligocene?). Therefore the sedimentaries are 

 not older than the OHgocene. 



The metamorphic sedimentaries exhibit a succession of beds 

 identical in its main features with the Philippine column of 

 Tertiary sedimentaries. The observed sections in the metamor- 

 phosed sedimentaries and in the unchanged sedimentaries 

 farther east are similar, although the lower part of the meta- 

 morphosed section is developed in greater thickness than the 

 corresponding division of the unchanged rocks. Moreover, in 

 ascending Caramoan River, one passes gradually from unchanged 

 sedimentaries to metamorphosed sedimentaries: that is to say, 

 there is an evident transition from one formation to the other 

 with no definite line of contact. 



In short, the schists and marbles appear to be no older than the 

 shales and limestones. Indeed these rocks appear to be different 

 sections of continuous beds which have been metamorphosed in 

 their westward extension but have escaped metamorphism 

 farther east. 



Thus the schists and marbles are likewise not older than the 

 Oligocene, and the antiquity which has been ascribed to the 

 metamorphic rocks generally in the Philippines is opened to 

 question. Paleozoic schists are found in Japan and in Formosa, 

 and they may exist in the Philippines, but the extensive area 

 of more or less typical schists on Caramoan Peninsula belongs 

 to a later period. 



The basal igneous complex upon which the Tertiary beds were 

 laid down obviously antedates these beds, but its age cannot be 

 more definitely fixed. The age of the schistose andesites, 

 grouped for convenience with the basal igneous complex, is like- 

 wise undetermined. 



GEOLOGIC HISTORY 



The geologic history of Caramoan Peninsula, so far as it may 

 be deduced from the data in hand, begins with an eroded pre- 

 Oligocene basal formation, principally a complex of igneous 

 rocks. From Oligocene time through to the Pliocene this basal 

 formation was submerged, and sedimentary rocks were laid down 

 over it. Whether each division of the sedimentaries is strictly 

 conformable over the preceding deposits is not certain, but no 

 unconformities were observed. The metamorphic andesite in 

 the western part of Caramoan was introduced, presumably as 

 a flow, during or preceding the deposition of the sedimentary 

 rocks. 



Dynamism, severe enough to change the sediments into true 



