Carbonate samples from Cretaceous rocks of Catanduanes Island and Caramoan Peninsula were subjected to paleontologic and petrographic analyses. The morphology of the Cretaceous Foraminifera and the petrographic characterization of the carbonates are described. The paleoenvironments inferred from the paleontologic and petrographic data are also given.

Orbitolina texana (Roemer) and Orbitolina cf. conoidea Gras, found in grainstones and packstones point to an late Early to early Late Cretaceous( Aptian to Cenomanian) age. A shallow water deposition is implied.

Other foraminifera under the genera Globotruncana, Globotruncanita, Rosita, Heterohelix and
Rugoglobigerina attest to a Late Cretaceous (Late Campanian to Early Maastrichtian) age. These fossils which are hosted in pelagic wackestones connote deposition in deeper waters probably either on the shelf margin or on the basin margin.

Lepidorbitoides (Asterorbis) sp., serving as an index fossil for a late Late Cretaceous (Late Maastrichtian) age, exists with rudists in packstones suggesting the relative shallowing of marine waters or uplift during that period,