SECTION 1. The barrios of Holy Friday, San Jose (East), and San Jose (West) in the Municipality of Roxas; the barrios of Casili, Olañgo 1.°, Olañgo 2.°, San Jose Nuevo, and Manano in the Municipality of Ilagan; the barrios of Barucbuc, Siempre Viva, Bimmonton, Pasurgong, Manga, and Settlement No. 1 in the Municipality of Tumauini; and the barrios of Abut and Minagbag, in the Municipality of Sto. Tomas, all in the Province of Isabela, are separated from said municipalities and are constituted into a new municipality in the said province to be known as the Municipality of Mallig, with the seat of government at the present site of the barrio of Olango 1.°, more definitely described as follows:
Beginning with M.B.M. 1, Mp. of Gamu, which is identical to M.B.M. 46, Mp. of Ilagan and designated as Corner "1" of the municipality herein created; thence N. 6° 38' W., 3644.33 m. to corner "2"; thence N. 6° 38' W., 4873.30 m. to corner "3"; thence N. 9° 27' W., 4685.98 m. to corner "4"; thence 27' W., 104.00 m. to corner "5"; thence N. to corner "6"; thence N. 15° corner "7"; thence N. 17° corner "8"; thence S. 58° corner "9"; thence S. 58° corner "10"; thence S. 4° 14594.29 m. to corner "11"; thence S. 4° 3252.31 m. to corner "12"; thence S. 4° 07' E., 4147.82 m. to corner "13"; thence S. 6° 31' E., 2345.50 m. to corner "14"; thence S. 8° 53' E., 92.67 m. to corner "15"; thence following Imbiao Creek downstream to corner "16", which is equivalent to M.B,M. 29 PLS-62; thence following Imbiao Creek downstream,, to corner "17", which is the intersection of Imbiao Creek and the Mallig River; thence following the Mallig River upstream to corner "18", which is the intersection of the Mallig River and that of the common old boundary line of Gamu and Ilagan; and thence from corner "18" following the Mallig River on a westerly direction to the point of beginning; containing an approximate area of twenty-eight thousand four hundred twenty-seven (28,427) hectares more or less.