中文摘要：

鄂西地区的长阳组长期划归下石炭统底部,所含Siphonodella levis带被认为是杜内期最底部的牙形刺化石带之一。根据新发现的牙形刺Icroides sp.,Polygnathus brevis,腕足类Cyrtospirifer sp.Schchertella gelaohoensis,和双壳类Buchiola sp.等化石现将该组改划为上泥盆统法门阶,与湖南中部的邵东组、孟公坳组、贵州者王组、革老河组等对比。牙形刺化石Sipho-nodella levis是法门晚期—杜内早期均有分布的种。

英文摘要：

Changyang Formation of western Hubei Province has been placed in the base part of Lower Carboniferous since it was set up in 1984.The Siphonodella levis zone occurred in that formation was treated as one of the lowermost conodont zones of Turnaisian for long time in China.On the basis of the new palaeontologic data including conodonts Icroides sp.,Polygnathus brevis,brachiopods Cyrtospirifer sp.Schchertella gelaohoensis,and bivalves Buchiola sp.,Changyang Formation is now assigned to the Famennian of Later Devonian.That formation may correlates with such rocks as Shaodong and Mengonao formations of Hunan Province,the Zewang and Gelaohe formations of Guizhou Province.The range of Siphonodella levis（Ni） may from the Famennian to Tournaisian,rather than the Early Tournaisian,as thought previously.