Breed of toy dog developed in the mid-19th century in Yorkshire and Lancashire, Eng. Its lineage appears to include terriers such as the Skye and Dandie Dinmont. Its outstanding feature is its straight, silky coat, parted on the back from nose to tail and long enough to sweep the ground. Its coat colour is dark blue-gray, with tan on the head and chest. It may grow to 9 in. (23 cm) tall and weigh up to 7 lb (3 kg).