78 ADAMS. 



quotation, which in part is : "all indicates a great volcanic center which 

 is lacking, but should lie where now the deep Einconada Bay is sunk." 

 The name Einconada refers to the middle lobe of the lake. Von Drasche 

 also says that Hochstetter unites this center of eruption with the Ma- 

 quiling and Malarayat-Sosoncambin Mountains in one system of volcanoes 

 which lie on a north-south fissure. He also quoted Eoth quite fully 

 concerning this area and then remarks that these observations correspond 

 very little with the view that an eruptive center should be sought in the 

 Einconada. 



One of the prevalent ideas concerning Bay Lake is that it was formed 

 by subsidence and may possibly be a crater of caldera similar to Taal 

 Lake. Dana discovered no evidence that the lake corresponds to a 

 single crater, and further states that Talim Island is probably a volcanic 

 summit, and another' small island ("Pulo Bay") off Bay consists of the 

 lavas of another. It seems that Hochstetter was correct in considering 

 that the eruptions occurred along the north-south line, since his field 

 observations show that the basalts extend northward to beyond Antipolo, 

 forming a rather definite zone bordered by tuffs and agglomerates. The 

 falls of Antipolo flow over this basalt. The origin of the lake is discussed 

 in a subsequent portion of this report. 



The "trachyte" described by Eichthofen as inclosing the limestone 

 northeast of Binangonan is a porous basalt often vesicular and frequently 

 brecciated. Basaltic flows, breccias and tuffs intermingled in great con- 

 fusion are found in the Binangonan-Talim zone. Susun-dalaga, the 

 highest peak of Talim Island, exhibits all these phases. Certain rocks 

 from this peak approach an andesite in composition. To the east of the 

 peak there is a bay in the island. The configuration of the island at this 

 point and the position of the islands near by have suggested to some 

 observers that the bay marks the position of a crater. No definite evi- 

 dence of a crater at this place was seen, but the peak is an important 

 point in the eruptive zone. The relations of Maquiling and Malarayat 

 Mountains to this zone will be discussed more fully in the part of this 

 report which deals with the southwest volcanic region. 



Some basalts and basaltic agglomerates were found near Tanay and 

 Pililla. They are probably related to those of the area just considered. 

 Ickis noted a dyke of basalt a short distance west of Tanay. Becker 

 described a labradorite basalt which he collected near Paete on the east 

 shore of the lake. Basalts occur at several places along the same shore 

 of the lake, and it is probable that they extend southward into the tuff- 

 covered area. 



Basalts were also seen just east of the landing at Mauban on the 

 Pacific coast and pebbles of basalt were found in a conglomerate on the 

 road from Mauban to Lukban. Large bowlders occur sparingly on the 

 adjacent uplands. Many streams of the eastern cordillera carry some 



