90 ADAMS. 



formation. The group of mountains southeast of the Pico de Loro 

 group has not been very thoroughly studied and it is possible that it 

 should be considered as related to the Pico de Loro group, but in this 

 report it is considered with the southwestern volcanic region, because 

 of the finding of extensive masses of basalt near the southern bases of 

 the mountains of the group, which class of rock is rare in the western 

 cordillera. 



The three peaks which are found near the border of Taal Lake have 

 been thought by some to be subordinate cones near the base of a supposed 

 former lofty cone of Taal, but the writer does not incline to this idea. 

 li they are related to a common center of eruption, they form a much 

 larger group than do the peaks related to Banahao. Careful petrographic 

 stud} r might show whether or not these mountains have had their origin 

 from the same magma. Macalod has the apperance of an independent 

 eruptive mass, with subordinate peaks, one of which is clearly defined 

 to the southwest of the main mountain. 



Cinder cones. — From the descriptions of the historic eruptions of 

 Taal Volcano and an examination of its crater it is evident that in 

 recent time no lava was ejected in the form of flows, but that bombs, 

 scoria and ashes have been thrown out. In other words, Taal Volcano 

 is a large cinder cone. A number of craters which are extinct occur on 

 Taal Island and examination of them proves that when they were in 

 eruption they likewise were of the cinder-cone type. 



Within the area of the tuff formation which has been built up from 

 the volcanic ejectamenta of the southeastern district, there are some 

 isolated cinder cones which still preserve indications of craters and no 

 doubt several of the smaller hills are the remnants of cinder cones which 

 have been largely eroded. South of- Lipa and near the road to Eosario, 

 there is a hill which has a slight depression in its summit, and around 

 this depression there is a crescentic rim on which scoria? are found. The 

 slope of the hill is covered with scoria? and lapilli. 



Just to the north of 'New Eosario there is a crescentic-shaped hill 

 which is a remnant of a cone. The hill is broken down to the northeast. 

 Masses of scoria outcrop on the higher part of the crater rim. A hill 

 which retains some of the characteristics of a cinder cone is situated to 

 the northwest of Batangas, but the rim and the crater are not very 

 well defined. To the west of the base of Maquiling there are a n amber 

 of hills which may represent small crescentic cones. About half-way 

 between Calamba and Santo Tomas and to the west of the road there 

 is a subcorneal hill formed of lapilli. This may be an eioded cinder 

 cone. The hill containing Laguna de los Caimanes, Pansol, the hill 

 on Mavondon Point and Cerro de la Mesa have been mentioned as 



