Ostracods from the Middle Jurassic Xintiangou Formation of eastern Sichuan Province, were investigated using Scanning Electron Microscope (SEM) for the first time. The porportions and distribution of some of the elements in ostracod shells (or valves) were also revealed by X-ray Energy Dispersive Spectroscopy (EDS) attached to the SEM. The authors show that these ostracod shells or valves have mostly been calcitized but in varying degrees in different layers of the Xintiangou Formation. The calcitization is probably related to the effect of organic matter. Comparison with previous studies indicates that the preservation of ostracods from the Xintiangou Formation is in the second and third stages in taphonomy.rosoft-com:office:office" />