88 EUITOKIAL. 



of the adjacent islands. The masses of marble obtainable near the port 

 are suitable for sawing into blocks and slabs. 



The marble has been used for paving floors in a few of the better houses 

 of Eomblon and it wears well. There are six holy-water fonts in the 

 San Sebastian Church in Manila each bearing an inscription indicating 

 that it came from Eomblon. These fonts of good workmanship and 

 pleasing appearance indicate that the marble is suitable for many uses. 



The so-called artificial stone manufactured in Manila is usually made 

 by mixing small pieces of Eomblon marble in a matrix of cement mortar 

 colored with various pigments. After the cement has set, the surface 

 is polished and the product is iised in trimming and ornamenting build- 

 ings, and for stairways. 



SCHIST. 



Lying to the west of the ridge of marble and well exposed at Binagon 

 Point on the west shore of the inner harbor, there is a schist formation 

 which strikes approximately K. 30° E., and dips about 30° to the west- 

 ward. Outcrops of the schist were seen farther to the west on Eosas 

 Point, Macaban Point, and undoubtedly it extends to the western point 

 of the island. It is also found on Agbatan Point to the north of the 

 harbor. To the eastward from the ridge of marble and to the east of the 

 town, the base of the hill slopes are composed of schist. This rock is 

 usually yellowish, but dark varieties also are found. It shows thin 

 laminse and Jointing in many places where it is weathered. It is 

 micaceous and siliceous and the fonnation contains occasional small gash 

 veins and stringers of quartz. In a few places schistose material was 

 seen in the marble near the contact of the two fonnations. 



ORIGIN" AND GEOLOGICAL SIGNIFICANCE OF THE MAKBLE AND SCHIST. 



The marble and schist were originally deposited as limestone and shale. 

 Their present condition is due to metamorphism produced by dynamic 

 action. The pressure which developed the laminated structiire in the 

 schist also produced a streaked appearance in portions of the marble, 

 which show the mixture of blue and white colors. No igneous rocks are 

 reported from Eomblon and the inhabitants say that the whole island 

 consists of schist and marble. There are some small bowlders of igneous 

 rocks lying on the sea wall near the landing stages, but they were brought 

 in as ballast. 



The northern point of the island is largely marble, as I observed when 

 leaving Eomblon on a steamship. Lugbung Island in front of the port 

 appears to consist mainly of schist, with some marble. Alad Island is 

 largely composed of marble and the northern point of Tablas Island 

 clearly shows great slopes covered with this unmistakable rock. 



Tablas, Sibuyan, and Eomblon Islands, together with some lesser 

 islands, constitute a small group in an interisland sea which is defined 



