ABSTRACT
Internal shell microstructures of molluscan fossils are important for paleontological and geological studies. The specimen, Lamprotula, of Early Pleistocene age, has well preserved internal microstructure which could be examined by the use of a scanning electron microscope. The shell structure is composed of a periostracum and calcareous shell layer. The latter is divided into three calcareous shell layers, namely outer, middle and inner. The outer consists of an aragonite layer which is made of prisms surrounded by preserved organic frameworks. The middle and inner layers consist of a nacreous film which is subdivided into pillow (lenticular) and sheet nacreous layers. The biomineral composition, aragonite is determined by the use of a X-ray diffractometer. A recent specimen was also studied for comparison. One important observation is that the inner calcareous layer is made of alternative layers of pillow and sheet nacreous structures.
