Argentiferous—Silver-bearing.
Argillaceous—Clay-bearing.
Arrastra—A rotary and primitive mill.
Assay—A test.
Assay-ton—29.166 2-3 grammes.
Auriferous—Gold-bearing.
Bar—Obstruction in the bed of a river.
Bar-diggings—Claims in the shallows of streams.
Base Metals—Those not classed as precious.
Batea—Mexican gold-washing dish.