The Yanks preferred dogs with erect ears which was fine with the French breeders as they preferred the rose eared specimens, as did the British breeders. (shrinkabulls.com)
A compact body, bushy tail, a pointed muzzle, and small erect ears characterize the breed. (puppiesdogs.org)
The easiest way to distinguish between the two is that Norwich terriers have pricked ears (like the steeple of Norwich cathedral) and Norfolk terriers have semi erect ears which are distinctly floppy looking. (pethelpful.com)