Nathan that he was certain of having killed only one Indian, during the battle at Blue Licks, although on another occasion he said, "I never killed but three." He expressed regret over the killings, saying the Indians "have always been kinder to me than the whites." Even though Boone had lost two sons and a brother in wars with Indians, he respected Indians and was respected by them. In Missouri, Boone went hunting with the Shawnees who had captured and adopted him decades earlier. Some 19th-century writers regarded Boone's sympathy for Indians as a character flaw and altered his words to conform to contemporary attitudes. The character John Boone in Kim Stanley Robinson's Mars trilogy is inspired by Daniel Boone. In the story, John Boone is an American astronaut, the first human to walk on Mars in the year 2020. John Boone is one of the "First Hundred" colonists sent to permanently colonize Mars. His accomplishments and natural charm yield him an informal leadership role. After being assassinated, his larger-than-life persona plays a legendary role in the culture of colonized Mars. Commemoration and portrayals Many places in the United States are named for Boone, including the Daniel Boone National Forest in Kentucky and the Sheltowee Trace Trail in Tennessee. His name has long been synonymous with the American outdoors. The Boone and Crockett Club is a conservationist organization founded by Theodore Roosevelt in 1887, and the Sons of Daniel Boone was the precursor of the Boy Scouts of America. A half-dollar coin was minted in 1934 to mark the bicentennial of Boone’s birth; a commemorative stamp was issued in 1968. In 1961, the US Navy ordered ten ballistic missile submarines to be made at the Mare Island Naval Shipyard. One would be named the USS Daniel Boone (SSBN-629), commissioning on 23 April 1964 and remaining in service until decommissioning in 1994. The submarine's motto "New Trails to Blaze" was an homage to Boone's life and his great legacy of exploration on the frontier. Boone's adventures, real and mythical, formed the basis of the archetypal hero of the American West, popular in 19th-century novels and 20th-century films. The main character of James Fenimore Cooper's Leatherstocking Tales, the first of which was published in 1823, bore striking similarities to Boone; even his name, Nathaniel Bumppo, echoed Daniel Boone's name. As mentioned above, The Last of the Mohicans (1826), Cooper's second Leatherstocking novel,