Blue transferware mug

I would like to know if anyone can recognize this pattern. It is a mug that was found by my father while scuba diving near the Fortress of Louisbourg, Nova Scotia in the late 70's or early 80's. It could have come from the fortress, or from one of the ship wrecks nearby. It is blue transferwares and is 4 inches high and 3.5 wide.

I have been told that it is refined earthenware, and the swag flowers around the base are Bluebells and others are possibly Anemone. I have contacted some experts but they were unable to give me a definite identification. It still remains a mystery so any help would be appreciated.