XI. A, 5 Pratt: Philippine Lakes 233 



northern shore. It is said to be subjected to fierce gales at short 

 notice, and the native boatmen are wary about venturing upon 

 it at certain seasons of the year. Fish are especially numerous 

 in Lake Mainit, and immense colonies of wild ducks and other 

 waterfowl make their home on its water. Crocodiles, also, are 

 said to be especially numerous in this lake. 



OTHER LAKES OF MINDANAO 



The only other lakes in Mindanao that are of the same order 

 of magnitude as Lake Mainit are swampy areas in the valleys 

 of the larger rivers. In the valley of Mindanao River, inland 

 from Cotabato, are three such bodies of water — Liguasan marsh, 

 Libungan marsh, and Lake Butuan. Liguasan marsh covers 

 an area of more than 100 square kilometers generally, but is 

 subject to overflow during the rainy season ; Libungan marsh is 

 somewhat smaller. Lake Butuan covers an area of approxi- 

 mately 59 square kilometers and is from 3 to 6.4 meters deep, 

 according to the Director of Coast and Geodetic Survey. These 

 bodies of water are only slightly above sea level, and their sur- 

 faces are largely covered by aquatic vegetation. Smith " con- 

 siders them to be remnants of a larger lake which formerly 

 covered the intervening low country. 



Lakes Dagum, Dinagat, and Linao and other adjacent smaller 

 lakes occupy a swampy area in the upper valley of Agusan River 

 in northeastern Mindanao. During flood periods these lakes 

 become one body of water — always shallow (30 meters, maximum 

 depth), but several hundred square kilometers in area. Their 

 level is very little above that of the sea. They are said to have 

 formed within historic times from subsidence or differential 

 elevation following earthquakes. Such an origin is possible, 

 since earthquakes are especially frequent and severe in Agusan 

 Valley, but it is worthy of note in this connection that a large 

 lake, Laguna de Mindanao, is shown on the upper Agusan on a 

 map published as early as 1734. 



Lake Leonard Wood lies north of Dumanquilas Bay in Zam- 

 boanga district at an elevation of 889 meters. The existence of 

 this lake was first reported to the American administration by 

 Captain C. C. Smith, Fourteenth Cavalry, United States Army, 

 who explored it in 1904 in the course of an expedition from 

 Misamis to Dumanquilas Bay. It is said to be like the figure 

 eight in outline and 3 by 8 kilometers in maximum dimensions ; 

 its area is probably 20 square kilometers. 



" Op. cit., 356. 



