The Native American in this story is portrayed as an Algonquin and he appears riding into town in full plains Indian headdress. There were no Algonquin Indians in Maine; Penobscott, Passamaquoddy, Abenaki, and Maliseet, but no Algonquins. It seems like five minutes of research would have provided a more accurate portrayal.
During the Founder's Day ceremony, Amos is wearing a tie, but when he Seth and Sam are driving to Algonquin Point his tie is missing. However, when they get to the point and are surveying the area mentioned in the letter his tie mysteriously reappears around his neck.