On 22 November 1976 A.D., a stone block set in September 1875 by topographical engineers of the U.S. Lake Survey marked the precise position of Paw Paw on the map of the world at 42 degrees, 13 minutes, one and 66-100 of a second north latitude and 85 degrees, 53 minutes, three and 31-100 of a second west longitude, and a large zenith transit observing instrument was mounted on top of the solid block.