ammite

from The Century Dictionary.

• noun An old mineralogical name for roestone or oölite, and for all those sandstones which, like oölite, are composed of rounded and loosely compacted grains. See oölite. Also written hammite.

from the GNU version of the Collaborative International Dictionary of English.

• noun (Geol.), obsolete Oölite or roestone; -- written also hammite.