You are right when you claim that Blombos, a seaside cave in South Africa, offers the earliest known evidence of human artistic production, going back more than seventy-thousand years (“Rates of Exchange,” June 9, 2007), but you are wrong about almost everything else concerning this archeological site. First, the discovery was made in 2001 rather than 2004, as you claim. Second, it was two pieces of engraved ochre that pointed at artistic production rather than the perforated seashells, as you state. By the way, the international press reported the engraved ochres, showing elaborate abstract patterns, in early January 2002, while you reported the discovery in late June of the same year—more than six months later. Now, the perforated seashells linking Blombos and the Grotte des Pigeons, a Moroccan cave of an even greater vintage, are quite important in tracing human development, as they may offer the earliest known evidence of a currency, but they do not bear any mark of artistic production.