This Article Hints the “Green Island of Survival” May Possibly, at least for a time, once again, be a Literal Island
The Ozarks, also referred to as the Ozark Mountains, Ozarks Mountain Country, and the Ozark Plateau, is a physiographic and geologic highland region of the central United States; primarily located in Arkansas and Missouri. The Ozarks cover a significant portion of southern Missouri extending as far northeast as the southwestern suburbs of St. Louis. In Arkansas, a large portion is contained within the northwestern and north central region. Much smaller pieces of the Ozarks extend westward into northeastern Oklahoma and extreme southeastern Kansas.
The Shawnee Hills of southwest Illinois, which lie near the eastern edge of this region, are commonly called the “Illinois Ozarks” but are generally not considered part of the true Ozarks.
Although referred to as the Ozark Mountains, the region is actually a high and deeply dissected plateau. Geologically, the area is a broad dome around the Saint Francois Mountains. The Ozark Highlands area, covering nearly 47,000 square miles (122,000 km2), is by far the most extensive mountainous region between the Appalachians and the Rocky Mountains. Together, the Ozarks and Ouachita Mountains form an area known as the U.S. Interior Highlands, and are sometimes referred to collectively. For example, the ecoregion called Ozark Mountain Forests includes the Ouachita Mountains, although the Arkansas River Valley and the Ouachitas, both south of the Boston Mountains, are not usually considered part of the Ozarks.
The Boston Mountains contain the highest elevations of the Ozarks with peaks over 2,500 feet (760 m)s and form the greatest relief of any formation between the Appalachian and Rocky Mountains. The Boston Mountains portion of the Ozarks extends north of the Arkansas River Valley 20 to 35 miles (32 to 56 km) and is approximately 200 miles (320 km) and are bordered by the Springfield and Salem Plateau to the north of the White River. Summits can reach elevations of just over 2,560 feet (780 m) with valleys 500 to 1,550 feet (472 m) deep (150 m to 450 m). Turner Ward Knob is the highest named peak. Located in western Newton County, Arkansas, its elevation is 2,463 feet (751 m). Nearby, five unnamed peaks have elevations at or slightly above 2,560 feet (780 m). Drainage is primarily to the White River, with the exception of the Illinois River. Many Ozark waterways have their headwaters in the uplands of the Boston formation, including the Buffalo, King’s, Mulberry, Little Red and White rivers.
Topography is mostly gently rolling in the Springfield and Salem Plateaus, where the Saint Francois Mountains are more rugged. The Springfield formation’s surface is primarily Mississippian limestone and chert, where the Salem Plateau is older Ordovician dolostones, limestones, and sandstones. Both are rife with karst topography and form long, flat plains. The formations are separated by steep escarpments that dramatically interrupt the rolling hills. Although much of the Springfield Plateau has been denuded of the surface layers of the Boston Mountains, large remnants of these younger layers are present throughout the southern end of the formation, possibly suggesting a peneplain process. The Springfield Plateau drains through wide, mature streams ultimately feeding the White River.