The Coastal Plains region is located in Arkansas, Texas, and Louisiana, and in southeastern Oklahoma. In Oklahoma the area lies south of the Kiamichi and Arbuckle mountains and north of the Red River and Lake Texoma and comprises all or part of nine counties. In the early twentieth century many lakes, including Arbuckle, Murray, Broken Bow, and McGhee Creek, were built in the area to stimulate the economy. The Glover River, the last remaining free-flowing river in Oklahoma, flows through the southeast of the region. High precipitation intensities and volumes (forty to sixty inches per year), mean annual temperature in the low sixties, and low occurrence of snowfall characterize the climate.
Coastal Plain geology includes association with the Trinity Group aquifer formation and Gulf Coast Plain formation, composed of Cretaceous-era nonmarine sands and clays. Most soils are deep, well drained, and moderately coarse-textured, except for a line of clays running northwest to southeast through Marshall, Johnston, and Bryan counties. Plants consist of non-native pine forests intermingled with hardwoods in the southeast and developing into oak savannah in north-central and western areas. Marsh-type plant communities exist along the Washita River and Red River drainages in central and southern parts of the region. Wildlife in the area consists of whitetail deer, wild turkey, quail, waterfowl, wild hog, small mammals, and successful reptilian communities.
Archaeological and anthropological study of the area indicate a society of Paoli Phase hunter/farmers (A.D. 900 to A.D. 1250) inhabited the Coastal Plains and developed into the Washita River Phase peoples. Archaeologists claim that around A.D. 1500 most of the Washita River Phase sites had been abandoned. In the seventeenth and eighteenth centuries the Kadohadacho occupied the extreme southern part of the Oklahoma Coastal Plains, along the Red River. In 1803 the United States acquired the area containing the Coastal Plains through the Louisiana Purchase. Prior to that time, the area had initially been under French control but changed hands from Spain to Britain and back to France over a period of about one hundred years. In 1830 the Treaty of Dancing Rabbit Creek allotted the Choctaw Indians the entire area of Coastal Plain in Oklahoma. The Chickasaw, who were more resistant to being moved from native lands in the east, arrived in Indian Territory later and settled on the western range of the Choctaw Nation.
In the twentieth century the region's industries grew to include timber (primarily pine) harvesting and wood-product manufacturing, as well as livestock production, row cropping, and forage production. The Coastal Plains also contains a plethora of well-developed municipalities where diverse service industries and the petroleum industry employ much of the population.
BIBLIOGRAPHY: James M. Goodman, "Physical Environments of Oklahoma," in Geography of Oklahoma, ed. John W. Morris (Oklahoma City: Oklahoma Historical Society, 1977). Kenneth S. Johnson, "Mountains, Streams, and Lakes of Oklahoma," Oklahoma Geological Survey Informational Series No. 1 (Norman: Oklahoma Geological Survey, 1998). Kenneth S. Johnson, et al., Geology and Earth Resources of Oklahoma: An Atlas of Maps and Cross Sections (Norman: Oklahoma Geological Survey, 1972). John W. Morris, Charles R. Goins, and Edwin C. McReynolds, Historical Atlas of Oklahoma (Norman: University of Oklahoma Press, 1986).
J. Josh Pittman and Richard A. Marston
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