The DeSoto Plain is a major geologic feature of Florida formed during the Miocene

Miocene

The Miocene is a geological epoch of the Neogene Period and extends from about . The Miocene was named by Sir Charles Lyell. Its name comes from the Greek words and and means "less recent" because it has 18% fewer modern sea invertebrates than the Pliocene. The Miocene follows the Oligocene...

 epoch and named for DeSoto County, Florida

DeSoto County, Florida

DeSoto County is a county located in the U.S. state of Florida. As of 2000, the population was 32,209. The U.S. Census Bureau 2005 estimate for the county is 35,406 . Its county seat is Arcadia, Florida. The county comprises the Arcadia, Florida Micropolitan Statistical Area.- History :DeSoto...

, United States

United States

The United States of America is a federal constitutional republic comprising fifty states and a federal district...

.

The DeSoto is an old prairie

Prairie

Prairies are considered part of the temperate grasslands, savannas, and shrublands biome by ecologists, based on similar temperate climates, moderate rainfall, and grasses, herbs, and shrubs, rather than trees, as the dominant vegetation type...

 or grassland

Grassland

Grasslands are areas where the vegetation is dominated by grasses and other herbaceous plants . However, sedge and rush families can also be found. Grasslands occur naturally on all continents except Antarctica...

 at elevations of 70 to 100 feet bounded by the lower elevation Okeechobee Plain

Okeechobee Plain

The Okeechobee Plain is a major geologic feature of Florida formed during the Pliocene and Pleistocene epochs and named for Okeechobee County, Florida, United States.-Description:The Okeechobee Plain is a dry prairie or grassland...

 on the east. It covers the counties of DeSoto, Manatee

Manatee County, Florida

Manatee County is a county in the state of Florida. According to the 2010 census by the U.S. Census Bureau there are 322,833 people living in Manatee Country.Manatee County is part of the North Port-Bradenton-Sarasota Metropolitan Statistical Area...

, Hardee

Hardee County, Florida

Hardee County is a county located in the U.S. state of Florida. As of 2000, the population was 26,938. The U.S. Census Bureau 2005 estimate for the county is 28,286 . Its county seat is Wauchula, Florida. The county comprises the Wauchula, Florida, Micropolitan Statistical Area.- History :It...

, Highlands

Highlands County, Florida

Highlands County is a county located in the U.S. state of Florida. The U.S. Census Bureau 2006 estimate for the population was 97,346. Its county seat is Sebring, Florida. The county comprises the Sebring, Florida, Micropolitan Statistical Area.- History :...

 Glades

Glades County, Florida

Glades County is a county located in the U.S. state of Florida. As of 2000, the population was 10,576. The U.S. Census Bureau 2005 estimate for the county is 11,252 . Its county seat is Moore Haven, Florida.- History :...

, and Charlotte

Charlotte County, Florida

Charlotte County is a county located in the U.S. state of Florida. As of 2000, the population was 141,627. In 2005, the population of the MSA was 154,030.The U.S. Census Bureau 2007 estimate for the county was 152,814...

.

The DeSoto plain was the ancient feature of Florida as the peninsula

Peninsula

A peninsula is a piece of land that is bordered by water on three sides but connected to mainland. In many Germanic and Celtic languages and also in Baltic, Slavic and Hungarian, peninsulas are called "half-islands"....

 formed over time. Edward Petuch writes that the DeSoto plain had rivers which poured sediment

Sediment

Sediment is naturally occurring material that is broken down by processes of weathering and erosion, and is subsequently transported by the action of fluids such as wind, water, or ice, and/or by the force of gravity acting on the particle itself....

s into the Polk Subsea during the Miocene's Serravallian

Serravallian

The Serravallian is in the geologic timescale an age or a stage in the middle Miocene epoch/series, that spans the time between 13.65 ± 0.05 Ma and 11.608 ± 0.005 Ma...

 and early Langhian

Langhian

The Langhian is, in the ICS geologic timescale, an age or stage in the middle Miocene epoch/series. It spans the time between 15.97 ± 0.05 Ma and 13.65 ± 0.05 Ma . The Langhian was a continuing warming period defined by Lorenzo Pareto in 1864, it was originally established in the Langhe area north...

 stages filling the Okeechobean Basin to the south. A large complex river delta

River delta

A delta is a landform that is formed at the mouth of a river where that river flows into an ocean, sea, estuary, lake, reservoir, flat arid area, or another river. Deltas are formed from the deposition of the sediment carried by the river as the flow leaves the mouth of the river...

 was formed between the time of the Polk Subsea and the creation of the Charlotte Subsea called the DeSoto Delta. This delta continued to carry sediments from a paleovalley on the DeSoto Plain and Lake Wales Ridge system region to the basin's western side. (Petuch, p. 50)