What is "guhr"

Guhr \Guhr\, n. [G.] 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.

n. A loose, earthy deposit from water, found in the cavity or clefts of rocks, mostly white, but sometimes red or yellow, from a mixture of clay or ochre.