Missouri is also known as the Cave State with more than 7,300 [2021] surveyed caves including 18 commercial caves open to the public [2021]. Kentucky, Tennessee, and Missouri are the States with the largest amount of caves in the United States. Missouri is divided into three parts:

  1. the the rolling plains of the prairie in the north,
  2. the ridges and deep valleys of the Ozarks in the southwest
  3. the flat delta area of the southeast

As the karst with its caves is concentrated at the Ozark area, we will do the same. Part of the Ozarks lies in RegionArkansas, so you will find some more caves there.

The Ozarks

Map of the Ozarks, U.S.A. Public Domain.
Dorsal, lateral, and ventral views of Typhlichthys subterraneus, Ozark cavefish, Amblyopsidae, U.S.A. Public Domain.

The Ozarks are called by geologists the Ozark uplift or Ozark dome. This area is the result of repeated episodes of submergence, deposition, uplift, and erosion. During times when the area was submerged under the ocean, limestone and dolomite were deposited. There were four mayor stages where limestone was deposited, the Cambrian Potosi Formation and Eminence Formation, and the Ordovician Gasconade Formation and Roubidoux Formation. The formations are separated by unconformities, where additional material has been eroded during exposed phases.

Younger rocks, deposited between 440 and 280 million years ago have been eroded completely during the last 280 Million years. During the last 280 million years, the area has been mainly in an uplift and erosion mode. The final major uplift took place during the Tertiary, between 50 million and 7 million years ago. The geological center of the uplift is located in the St. Francois Mountains in southeast Missouri. These are the oldest rocks in the Ozarks, the exposed core, located in the St. Francois Mountains. Like a huge dartboard, the rocks get younger in irregular bands moving outward from the St. Francois Mountains.

There are two mountain ranges in the Ozarks, the Boston Mountains in Arkansas and the St. Francois Mountains in Missouri. The highest point is Buffalo Lookout in the Boston Mountains. The rest is divided into two subregions, the Springfield Plateau which extends over southwest Missouri, northeast Oklahoma, and northwest Arkansas, and the Salem Plateau or Central Plateau, which includes a broad band across south central Missouri and north central Arkansas. Karst features are common in the limestones of the Springfield Plateau and abundant in the dolomite bedrock of the Salem Plateau and Boston Mountains.