From http://www.bumperfound.org/ .
This golden retriever mix shows the black and tan coloration that was once so prevalent in his ancestors: the St. John’s water dog and the wavy-coated retriever. Landseer had painted a dog very similar to this one.
If such a dog were placed in the nineteenth century, he would instantly be recognized as a retriever.
Today, we might also mistake black and tan English shepherds for this dog. This makes some sense, though, because both of these dogs descend, at least in part, from the old-type collie farm dog.
I wrote some more about this coloration last week.