This is a postcard of "Champion" Black Sambo owned by Hal Duffett, Terra Nova Kennels reg'd Breeders of the famous Newfoundland Dogs. The Willows Marine Drive, St John's NFLD. This postcard is from the early 1980's.
The Newfoundland is a breed of large dog. Newfoundlands can be black, brown, gray or black and white. They were originally bred and used as a working dog for fisherman in the Dominion of Newfoundland. They are known for their giant size, tremendous strength, calm disposition and loyalty. Newfoundland dogs excel at water rescue/lifesaving due to their muscular build, thick double coat, webbed feet and innate swimming abilities. Males weight range 130-150lbs, females 100-120lbs.
In the water, the dog's massive webbed paws give it maximum propulsion. The swimming stroke is not an ordinary paddle. Unlike other dogs, the Newfoundland moves its limbs in a down-and-out motion, which can be seen as a modified breaststroke. This gives it more power with every stroke.
Many tales have been told of the courage displayed by Newfoundlands in adventuring and lifesaving exploits. One famous Newfoundland was a dog named "Seaman", who accompanied American explorers Lewis and Clark on their expedition. 
I have only met a Newfoundland Dog once in my life. This happened about a year ago while in the Pet Store, getting food for my Golden Retriever. Being the Dog Lover that I am, and having a mother who was born in Newfoundland, I quickly made my way over to this handsome black stoic creature and his owner. I found him to be extremely friendly and well mannered. His owner told me all about him and her life with this "gentle giant". I hope to meet a Newfoundland Dog again someday.
The photo on the right is of my Golden Retriever "Lucy". She is the 3rd Golden Retriever I have been fortunate to live with. I have learned that the Golden Breed is a cross between the Irish Setter, the sandy-colored Bloodhound, the St John's Water Dog of Newfoundland and the wavy-coat Black Retriever.  Although Golden's are not as large as Newfoundlands, they share similarities of being good natured, loyal, and strong. So, Lucy has a little "Newfie" in her too.
 Newfoundland (dog) http://enwikipedia.org/wiki/Newfoundland_(dc
 Golden Retriever, History http://enwikipedia.org/wiki/GoldenRetriever