Abstract: This paper deals with some fossil woods found in a hill near to Xiadelongwan village, Yanqing district, about 120 km north of Beijing. There are more than 30 thick fossil trunks 0.6–2.5 m in diameter. They arc erect above the ground 30–50 cm, grey, light brown and grey-black in color. Two species are identified: Xenoxylon latiporosum (Cramer) Gothan and X. sp. along with Zamites sp. and Neocalamites sp. All of them are from the Houcheng Formation of late Middle Jurassic. These fossils are well- preserved. It show that the climate of Beijing by the Middle Jurassic was subtropical, hot and damp, rich in rainfall. The well-marked growth-rings of these woods show that the seasonal changes were quite clear. Spring woods are very wide which indicates that the growth rate was very fast.

Key words: Beijing, A petrified forest