Several layers of K- bentonite are exposed from the Wufeng Formation, upper Ordovician in the Huanghuachang area of Yichang, Middle Yangtze. The bentonite is composed mainly of the illite- dominated clay minerals, with some hexagonal bipyramid quartzs, zircons, apatites, iron microspheres, etc.. The geochemical composition has the characteristics of arc volcanic rocks. The first layer in the Wufeng Formation has ε Nd ( t ) of -3. 83 and the zircon U- Pb age of 445. 4±2. 0 Ma, the zircon ε Hf ( t ) value of 2. 7 to 7. 3, the weighted average value of 4. 67±0. 89， the t DM2 is 965 to 1249Ma, the weighted average age is 1127±55Ma. The eighth layer in the Wufeng Formation has ε Nd ( t ) of -7. 92, the zircon U- Pb age of 444. 1±2. 2 Ma, the zircon ε Hf ( t ) value of -6. 6 to -11. 2, the weighted average value of -8. 74±0. 88, the t DM2 of 1840 to 2130 Ma and the weighted average age of 1973±55 Ma. The mineral composition, geochemical elements, zircon U- Pb ages and Hf isotopes of K- bentonite indicate that it may derive from the volcanic eruptions in the Qinling Mountains of in the northern margin of the early Paleozoic Yangtze, and the age of the Linxiang and Wufeng formations are limited in 445.4Ma. The frequent occurrence of these bentonites marks the beginning of the extinction and replacement in the late Ordovician.