PAPERS OF GENERAL INTEREST 39 



age surface. There are two such areas in Hardin county, 

 one in the vicinity of Cave in Rock and the other near Rosi- 

 clare. There are other similar areas in Johnson and Pope 

 counties. 



Some idea of the rug-gedness of the Ozarks can be gained 

 by a more detailed statement of the steepness of the slopes 

 in various parts of this highland region. On the Mobile and 

 Ohio railroad from Pomona to Alto Pass, in a distance of 

 four miles, the altitude changes from 403 to 748 feet, while 

 in the next four miles there is a drop from 748 to 449 feet. 

 Again at Ozark on the Paducah branch of the Illinois Cen- 

 tral railroad there is a descent from 668 feet, at Ozark, to 

 384 feet at Simpson, in a distance of five miles. It should 

 be noted that these are railroad grades and are about the 

 easiest grades that can be found which cross the crest of 

 the Ozarks. Most of the side slopes of the valleys are very 

 much steeper. Slopes of 600 and 700 feet per mile are 

 numerous and in not a few cases slopes of 800 to 1000 feet^ 

 per mile are to be found in all regions of strong relief. 

 Much steeper slopes than these are found in restricted areas. 

 In fact one of the characteristic features in many parts of 

 the Ozarks is the bluff or almost peiT3endicular cliff. In 

 many cases these perpendicular cliffs form the most strik- 

 ing feature of the surface. High bluffs are particularly 

 noticeable in Big Hill at Leo Rock and Fountain Bluff, along 

 the lower course of the Big Muddy, bordering the Mississ- 

 ippi flood plain in the chert hill regions in western Union 

 and northwestern Alexander counties. Other bluff regions, 

 perhaps a little less noticeable, are to be seen along the 

 Cache-Big Bay bottom lands that form the southern bound- 

 ary of the Ozarks. Bluffs are also found along the Ohio 

 river. There are various other situations where bluffs are 

 to be seen bordering even some of the smaller streams in 

 the interior of the Ozark region. Most of these bluffs are 

 due to undercutting of streams, but faulting and weak rock 

 layers underlying stronger rocks are also important causes. 



Perhaps no better idea of the ruggedness of the Ozarks 

 can be gained than from some quotations from geologists 



3. Salisbury: Extract from Bull. No. 41, 111. State Geological Survey, 1920, 

 page 43. 



