I'm trying to identify the maker of these plates for the museum I'm working at. Donor lore says these pieces came across the Oregon Trail in 1848, and I'd like to confirm that the dates are appropriate. The makers marks are muddy, but clearer versions say "Meissen England." Meissen is a German company, and from what I can tell, they never made ceramics in England. The blue onion pattern was much copied, so I'm guessing some English potter copied the pattern, and then called the design Meissen (cheeky, but whatever). Any help you can give would be much appreciated. All my usual sources are being unhelpful.