Submarine erosion surfaces are a little known but probably quite common feature of shallow marine shale successions. Differences between the Appalachian Basin and the American Craton.
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Click on the image to get a larger, high resolution picture. Shows several inclined truncation surfaces within black shales. Note angular truncation of beds beneath truncation surfaces. Shales deposited after an erosive event are conformable to the underlying erosion surface. Their draping over these truncation surfaces produces a kind of pseudo cross-stratification.