Walsh also wrote of the Fox Terrier (or, rather, of its cross-breed ancestor): "The field fox-terrier, used for bolting the fox when gone to ground, was of this breed [bull and terrier]." Not only is the Fox Terrier the progeny of the bull-and-terrier, [15] but so is the Airedale Terrier , [16] rat-working terriers, working black and tan terriers and most all other vermin-hunting terriers.