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The main cave at Roc de Marsal is part of a larger system of solution cavities formed in a Cretaceous limestone that includes a number of lithological beds distinguished, in part, by their texture, composition, and degree of consolidation. The bedrock floor, as it existed just prior to initial occupation, is a highly irregular and complex erosional surface that had truncated some of these beds. At its lowest point, more or less in the center of the cave, this floor is a basin-like de-pression, while toward the back of the cave it rises abruptly approximately one meter higher (see figure). |
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In the rear of the cave, some of the limestone beds include irregularly shaped, sub-horizontal, erosional endokarstic tubes that had been filled with sediments that accumulated prior to and perhaps during occupation.
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