The manganese deposits that occur on the east side of the Great Valley of the Appalachians from Virginia to Georgia are found chiefly near the contact between the dolomite sequence and the underlying quartzite sequence of the Lower Cambrian series. Recent studies in northern Tennessee show that the manganese oxide occurs in clays residual from impure limestone associated with glauconitic quartzite in a transition zone between pure dolomite above and pure quartzite below. It is suggested that the manganese was derived from residual grains of manganese carbonate or oxide minerals that were concentrated with round quartz grains on an old land surface by weathering and redeposited as a marine sediment in which calcareous silt and glauconite grains were being deposited.

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