Hoffman, Walter E., Merryweather, Algernon (1848). 36N 20W - Survey Map of Gull Island, St. Martin Island and Gravel Island, Fairbanks Township, Delta County, Page 2 [Michigan]. Department of Natural Resources. https://michigan.access.preservica.com/uncategorized/IO_8cd84e9e-5b0f-430f-94b8-b5b7b47d6c59 (map)