21. Then there is black shale or slate matching the Luarca Slate of Llanvirn to Caradocian Age. 22. In the Paleocene ( ) dark black shales mark the lack of oxygen in stagnant water. 23. The Upper Ordovician Lower Silurian materials there contain a roughly thick, carbon-rich layer of black shale . 24. Its bedrock is Precambrian-era gray and black shale . 25. But the clincher was the green itself, backed by an amphitheater-like natural outcropping of black shale . 26. The deposit was formed by remobilsation of uranium already enriched in the black shales by synsedimentary processes. 27. The rock underlying the dam is Ohio Black Shale which is a largely hard, massive silt shale. 28. A rock formation known as the Campbell's Ledge Black Shale occurs in the vicinity of Leggetts Creek. 29. Calcareous shales and black shales also occur. 30. Wismut explored a black shale -type uranium mineralisation below the villages of Hauptmannsgr�n and Neumark, Saxony west of Zwickau.
