BY THE REV. J. E. TENISON-WOODS, F.G.S., &C. 717 



the tufaceous region of the volcano of Taal, attains to considerable 

 thickness in certain localities, with a distinct structure in its cinders 

 and pumice according to the extent and duration of the various 

 volcanic eruptions. In making the excavations connected with the 

 Manila Waterworks the tufa has been sunk through for nearly 

 30 feet. The section showed that the different strata were 

 separated by a deposit of fine volcanic sand, which marked the 

 period of comparative repose in the eruption. Thei'e are, of course 

 many other extinct volcanoes in the region now referred to, such 

 as Banajao, Majajay, Maquilin, and many others on the side of 

 Laguna de Bay. But some of these have not been in activity 

 within I'ecent times, yet it is thought possible to assign to each 

 whatever share it may have had in producing the tufaceous deposits. 

 This will be considered by some to be open to question, but, at any 

 rate, there can be no doubt that a very lai'ge quantity of ash 

 deposit has come from the volcano of Taal, and that this quantity 

 is largely in excess of what can reasonably be attributed to the 

 present crater. 



The physical geography of the Laguna of Bombon is an argument 

 which is also relied upon. It is separated from the sea by only a 

 A^ery narrow strip of land, and this is entirely composed of ash 

 deposits. The lake itself is brackish, and has an extensive marine 

 fauna in its waters. They said that sharks are found in it to an 

 extent which prevents the natives from venturing into its waters 

 at any distance from the shore. 



It is hard to see how these facts can be regarded as settling the 

 matter one way or the other. Supposing the lake to have been 

 separated from the sea by the gradual filling up of a narrow strip 

 of land through which the river Pansii^it now flows, the appearances 

 would be still the same. As to the fishes, it is a well-known fact 

 that sharks will ascend fresh-water rivers for a considerable 

 distance, besides other marine fishes. The fishes that I saw 

 amongst the inhabitants of the lake were fresh-water Siluroids, 

 and the mollusca were decidedly fresh-water, including the genera 

 Mslania, Paludina, Unio, Cyrena, and Gorbicula. The same species 

 are found in the Laguna de Bay. 

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