ON THE YOHLU SANDSTONE

The Yohlu sandstone is a quartzitic sandstone, spreading very widely in the Hunan Pro-vince. The name was proposed by C. C. Tien in 1927-1938. The typical locality is Yu-lu-shan near by Changsha, but no good determinable fossil was found since then. This series wasconsidered by C. C. Tien (1938) as Upper Devonian in age with no palaeontological evidence.It is equivalent to the marine Hsikuangshan Limestone. Many Geologists hold Tien's opinion,while others consider it to be Devon-Carboniferous or Lower Carboniferous. The Yohlu sandstone as observed at many localities lies conformably between the marinefossil bearing Lower Carboniferous Mengkungao series (Tounasian) and the Upper DevonianHsikuangshan limestone (Famenian). On the basis of the field observation from Yoh-lu-shan, the Yohlu sandstone may. be sub-divided into two parts, they are: (1) Upper formation: It is a thick quartzitic sandstone with grey thin-beded shale, containingfossil plants 2000 m. (2) Lower formation: It is a thin quartzitic sandstone intercalated with grey thin-beded shale,containing fossil plants 50 m.The upper formation lies directly upon the lower formation without any hiatus. From the foregoing description, we know that the Yohlu sandstone may be subdivided intotwo fossil beds: The lowermost part of the upper formation contains Lepidendron sp. (n. sp. ?),Cycostigma cf. asiaticum, Cycostigma spp., Platyphyllum sp. (n. sp. ?); the uppermost part ofthe lower formation contains Cycostigma kiltorkense Haugton, C. spp., ?Sublepidodendron sp.,Platyphyllum sp. (n. sp. ?), Taeniocrada spp., Sphanopteridium spp. etc. A single specimen probably representing a new form of Lepidodendron is found from thelowermost part of the upper formation of the Yohlu sandstone. From the shape of the leaf cus-fious, its age is quite probable not older than the Lower Carboniferous. But among the fossilplants from the uppermost part of the lower formation, Cycostigma kiltorkense Hanghton is anindex fossil of the Upper Devonian in the world. According to the cycle of sedimentation, the diastrophism, the faunal assemblage, the palaeo-geography, and the geotectonics, the writers hold that the Yohlu sandstone is a member of UpperDevonian to the Lower Carboniferous, and is equivalent to the Wutung Series (Wutungnian) ofSouth-Eastern China or the Etroungtian of Western Europe.