1938 - Pan American Airways System Fairchild 71 and downtown Miami
Miami, Florida
The state archives says this is at Dinner Key but the downtown angle is wrong so I suspect it is on Watson Island. Thank you to Mark Lincoln for identifying the aircraft type.
You are right. This photo could not have been taken at Dinner Key. The airplane is a Fairchild 71. Pan Am operated 3 of them between 1930 and 1940. The Fairchild 71s (and the similar Fairchild FC-2 5 of which were operated by Panagra) were operated in Central and South America. The Fairchild 71 (and FC-2) could be operated on wheels or floats, but were not "amphibious." Looks like the Florida State Archives has it wrong again.