I adopted a 4yr old dog from our local humane society today and was told he is an Australian Sheep dog/Border Collie mix, but he doesn't look like either one to me from what I've seen on various websites. He's black and tan, with perfect facial markings, black forehead & snout,tan cheeks and tan around his big brown eyes, with a perfect black streak from his nose up to his forehead. He's flat coated, long haired, with flat ears and his body is 18" tall. His back and tail are black, and his legs, lower chest and tummy are tan. He is incredibly low keyed, soft and gentle. Can anyone give me an idea of "what" he is? I'd appreciate it - thank you.