Newfoundlands were used for retrieving shot birds. Yes, this includes the large black and white dog that eventually became the modern Newfoundland and FCI Landseer breeds.
This painting is by Edmund Bristow.
So yes, Newfoundlands were used as retrievers in both the United States and Europe.
One of the problems in determining what dogs were in the early retrievers is that Newfoundland could refer to the St. John’s water dog and the large black and white dog.
Audubon and Lewis and Clark both had Newfoundlands, but no description of these dogs exists. My guess is that they were of the proto-Landseer and Newfoundland type, not the St. John’s water dog type.
The Chessies are said to come from Newfoundlands, but my guess is these come from more of the St. John’s water dog type, which is why they look more like retrievers and have the brindling that was associated with the St. John’s water dogs.
Breed clubs are forever coming up with stupid histories, which are often parroted by the gullible. The trouble with all that is that actual historical records are something else.
There were two dogs called Newfoundland and both hauled nets and retrieved. The larger ones hauled carts and sleds. The smaller ones moonlighted as upland game retrievers, but both became part of the early retriever lines when they were exported to Europe.
But I do know two things about the St. John’s water dog and the Newfoundland. They are not descended from Norse dogs. These dogs would have had to have lived with the Beothuck when the Norse finally abandoned their colony on the island. Unfortunately for that theory, the Beothuck were conspicuously without dogs when the Basque, Portuguese, and English came to fish and whale Newfoundland’s waters.
Of course, none of that matters, when breed clubs keep saying that the dogs are derived from Leif Ericsson’s “Viking bear dog.” It simply isn’t true. The so-called bear dogs were mastiffs similar to the Dalbo-dog and the Broholmer. However, there is not a shred of evidence that these dogs lived on in North America after the Norse left. It’s a flight of fancy.
Now, it is possible that husky-type dogs from Labrador (of the North American hauling spitz type) may have played a role in their development. It is also possible that the Native American dogs that were used to retrieve ducks shot from canoes were used in their development.