Lewisville Prehistoric Site. During the construction of Lewisville Dam in 1950, a number of aboriginal artifacts were unearthed; archeologists conducted several excavations (1952-57) before the waters of Garza-Little Elm Reservoir covered the site. The excavations revealed 21 hearths, vegetable matter, animal bone fragments and lignite (coal) which was used for fuel. Scientific radiocarbon dating techniques indicate the organic material is approximately 12,000 years old. The Lewisville discoveries are similar in age and content to findings at the Clovis site in New Mexico. (1980) #3080