The Citronelle Formation is the principal source of sand for concrete and other uses in Florida. It underlies a highland region, known as the Lake Wales Ridge along the axis of the Florida Peninsula, which is attributed to upwarping and erosion of the Citronelle. The slopes of the base of the formation, the origin and distribution of clays, and the absence of fossils are evidence against origin as offshore bars. Difference in the heavy-mineral suite indicate that it is not a terrestrial facies of the marine Hawthorne Formation of Miocene age, and it is probably younger. Its composition and sedimentary structures indicate a fluvial origin.