Abstract:
Important Middle Permian index fossil of brachiopod, Leptodus, which preserve with softpart instead hard part like another one’s genus is studied by geology and paleontology for reconstruct paleoenvironment and paleoecology. Part of Amphoe Bueng Sam Pan and Amphoe Nong Phai in Changwat Phetchabun is study area. Lithostratigraphy was constructed and the samples were collected in field work. After that was prepared and studied thin section in laboratory. In fossil localities found 69 Leptodus, size frequency length is about 13-15 mm. Identified to L. sp. Cf. L. nobilis (Waagen, 1883), that found in muddy limestone, fresh color is grey-black, weather color is brownish gray. And found in silicified mudstone too. The associated fossils are bryozoa, algae, crinoids, bivalve, and another genus of brachiopod. By all result, associated fossils, lithostratigraphy and thin section can reconstruct paleoenvironments to shallow marine, in barrier reef top community.