One hundred and four species of fossil mollusks were identified from a collection taken from twenty-one localities distributed in five sedimentary formations of (?} Oligocene to Quaternary age in the Iloilo Basin. Thirty three other forms were identified up to generic level. Twenty-three species belong to eight families under Class Pelecypoda; one hundred and twelve species represent twenty-six families in Class Gastropoda and; five species belong to Family Dentaliidae under Class Scaphopoda.

The study revealed particular associations and a certafn pattern of stratigraphic distribution among the species represented.