Report of State Geologist, 18Q6. WASHINGTON's Monmlent
Report of State Geologist, 18Q6. PLATE IV. WASHINGTON'S MONmlENT MARENGO CAVE. INDIANA CAYES AND THEIR FAUNA. BY W. S. BLATOHLEY. The Bubcarboniferous limestone area of southern Indiana contains many sink holes and caves within its bounds. This area is, for the most part, embraced in the counties of Owen, Monroe, Lawrence, Washington, Orange, Harrison and Crawford. Going southward from the center of the State, the sink holes first become a prominent feature of the surface in eastern Owen and western Morgan Counties, and are found in num bers thereafter, in the area mentioned, until the Ohio River is reached, beyond which, in Kentucky, they are said to be still more numerous, in Sink many portions of the State averaging 100 to the square mile. These sink holes vary much in size, sometimes being but a Holes. rod or two across, and again embracing several acres in extent. They are, for the most part, inverted cones or funnel shaped cavities, and, where small, usually have the sides covered with a matt~d growth of vines and shrubs. Where larger, trees of varying size are often found growing from the scanty soil on the sides, or from the bottom of the sink. If one will examine closely the lowest point of a sink hole, he will usually find a crevice or fissure through the limestone, or sometimes a la~ge opening which, if it be possible to enter, will be found to lead to an underground cavity-a cave. Both sink holes and caves not only owe their origin, but usually their entire formation, to the slow, unceasing action of rain or carbonated water upon the limestone strata in which they occur.
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