What is a loose, earthy deposit from water, found in the cavities or clefts of rocks, mostly white, but sometimes red or yellow, from a mixture of clay or ocher. P. Cleaveland called?

guhr — A loose, earthy deposit from water, found in the cavities or clefts of rocks, mostly white, but sometimes red or yellow, from a mixture of clay or ocher. P. Cleaveland. (Webster's 1913.)