The prehistoric mounds in the Mississippi Valley present evidence of the estimation in which pearls were held by a race of men who passed away ages before America was first visited by Europeans. In some of these mounds, erected by a long-forgotten race, pearls have been found not only in hundreds and in thousands, but by gallons and even by bushels. Some of these equal three quarters of an inch in diameter, and in quantity exceed the richest individual collections of the present day. Damaged and partly decomposed by heat and through centuries of burial, they have lost their beauty, and are of value only to the archæologist and to indicate the quantity of pearly treasures possessed by these early people. Owing to the great wealth of pearls which had been uncovered on the Spanish Main, at Panama, and in the Gulf of California, Eldorado explorers, in the sixteenth century, were particularly eager in searching for them within the present limits of the United States; in the reports of their wanderings, much space is given to these gems, and these reports aided largely in inducing and encouraging other expeditions. Some of these accounts read like the marvelous stories of Sindbad the Sailor, quantities of pearls—hundreds of pounds in some instances—being secured by the exchange of trinkets and by more questionable means. It would be easy to bring together numerous accounts of apparently reliable authorities to show that in the sixteenth century pearls were obtained here in far greater quantities than were ever known in any other part of the world; but this conclusion seems not wholly correct. The unfortunate wanderings of Hernando de Soto from 1539 to 1542 gave rise to most of the reports of rich pearl finds within the limits of this country. Of this voyage there are three principal accounts. The first was by Luis Hernandez de Biedma, who had accompanied De Soto as factor for Charles V of Spain. His brief report was presented to the king in 1544, although it was not published until 1841, nearly three centuries later, when it appeared in a French translation.[300] The second, and in our opinion the most reliable account,[301] published at Evora in 1577, was by an unnamed Portuguese (in English editions, commonly spoken of as the Gentleman of Elvas), who was a member of the expedition. The third account,[302] by far the longest and most widely known, but which was not written until 1591, was by Garcilasso de la Vega, who represented that his information was from a Spanish cavalier who had accompanied De Soto.