Examination of Holocene Bahamian oölites by scanning electron and light microscopy has revealed the morphology and orientation of aragonite crystals in the lamellar oölitic envelope, and their modification by the boring activities of endolithic algae. The voids produced by these algae are found in progressive stages of being lined and filled with precipitated microcrystalline aragonite, which is similar to the process of micrite envelope formation in molluscan and other skeletal carbonate grains, as described by Illing (1954) and Bathurst (1966).

Areas in the outer portion of the oöliths that contain algal borings filled in with micrite are shown to represent the crypto-crystalline unoriented lamellae described by Newell and others (1960). The oriented prismatic layers in Bahamian oölites, on the other hand, contain minute aragonite crystals with their c-axes oriented roughly parallel to the layers, as suggested by Newell and others (1960) and Cloud (1962).

Similar scanning electron microscope techniques when applied to the study of Holocene and ancient carbonate sediments will clarify our understanding of the micritization process.

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