CHAPTER VI. 
ORE DEPOSITS. 
Geography. 
On the accompanying map, plate X XI, the location of the 
principal mining camps of the Ozark district are represented 
in red, and also the axis of the Ozark area. The map, plate 
III, gives a more detailed illustration of ore bodies in the 
Kansas mining area. It will be noted that all of the princi- 
pal mining towns in the southwestern district, with the ex- 
ception of Aurora and Wentworth, lie within a zone about 
ten miles in width which very closely parallels the axis of 
the Ozark area. This same condition is shown to be true 
elsewhere. ‘The lead and zinc ores of Hickory, Benton, Mor- 
gan, Camden, Cole and Miller counties in the central district, 
and of Franklin, Jefferson, Washington, Ste. Genevieve, St. 
Francois and Madison counties in the eastern district, and the 
ore bodies near the boundary line between Arkansas and Mis- 
souri, on the south, all liein this peripheral zone. The mines at 
Aurora and Wentworth lie farther up, or nearer the summit 
of the area. No other mines have yet been opened up which 
have a production of any considerable commercial importance. 
And yet Aurora is not so very far from the peripheral zone, 
and to a great extent may be considered within it. This ar- 
rangement of ore bodies is believed to be based upon causes 
connected with the origin of the ores, namely, the areas 
throughout which the rocks are fractured to the greatest ex- 
tent in part, and to certain coincidences of lithologic condi- 
tions and structural relations, such as unusual amounts of 
flint or chert in the Mississippian limestone of the Galena- 
Joplin district and the peculiar geologic conditions which 
brought the ore-bearing Silurian limestone near to the sur- 
face in the eastern area. 
(104) 
