My observations of the general features of the country in 1821 led me not merely to doubt, but to deny altogether, that there is any reason for referring the denudatory action to which its valleys are due to any single cataclysm or diluvial phenomenon.
Source: wiktionary
Not even the underclay, with its matted, carbonised roots, is sufficient evidence of the nearness of a bed of coal, for such a material has sometimes been deposited, and either the conditions for the abundant growth of the coal-plants have not supervened, or the coal may have been formed, and subsequently been removed by natural denudatory action.
Source: wiktionary