Analyzing and Mapping Natural Landscape Factors—Ozark Province 49 
dolomite contains very little chert and has moderate absolute 
resistance. Consequently, it weathers and erodes more rapidly 
than does the limestone, leaving fine-textured residuum which 
washes readily on slopes. On hillsides the resulting thin layer 
of mantle rock is kept moist by horizontal seepage from bedding 
Pianes in the dolomite, but on hilltops it is dry, except after 
rains. The remaining formations of the region, Chattanooga 
shale, St. Peter sandstone, and Everton limestone, have low to 
moderate absolute resistance, the Everton being the most durable 
of the three. Mantle rock derived from these formations is 
chert free, but varies in character, the Chattanooga and Everton 
yielding clays and the St. Peter sand. 
Deep dissection by dendritic streams has produced a strik- 
ing intaglio pattern of rock outcrops. The higher hills are capped 
by Burlington-Boone limestone which is overlaid by its residual 
chert and rests unconformably upon various other rocks of lower 
absolute resistance. Of these latter, the Jefferson City-Cotter 
dolomite has the greatest outcrop area, whereas the other forma- 
tions, the Chattanooga, St. Peter, and Everton, have more limited 
€xposures within the region. 
Probably the most important single factor in the regional com- 
plex is the high differential resistance between the Burlington- 
Boone and the weak beds below it. The order of superposition of 
the rocks makes differential resistance very effective. The Burling- 
ton-Boone chert residuum caps its parent limestone and protects it 
from erosion, whereas the limestone, itself, acts as a cap for 
the underlying Jefferson City-Cotter and other weak formations. 
Within the Burlington-Boone Cap Regions minerals are un- 
important. Sphalerite, smithsonite, and calamine (zinc minerals ) 
centr with galena (lead sulphide) in beds, breccias, and veins 
'm voth the Burlington-Boone and the Jefferson City-Cotter form- | 
ations. These deposits are not being worked at present. 
