CONCLUSIONS AND RESUME 239 



question of the origin of the ores and causes of mineralization. It 

 practically negatives, it would seem, the idea entertained by some that 

 the lead and zinc ores in general were brought from great depths by hot 

 waters and scattered throughout the rocks adjacent to deep reaching 

 fissures. 



Conclusions 



From the foregoing discussions it may be concluded that the mineral 

 area of southern Missouri and adjacent territory owes its existence as 

 such to the peculiar relations existing between the fractures produced 

 in the formation of the Ozark monoclinal uplift and the character of the 

 rocks covering the area. The ore deposits are most abundant where the 

 nature of the fractures permits the greatest freedom in ground water 

 circulation, w T hich is around the borders of the uplift. The character of 

 the rocks likewise has had a great influence on the kind and abundance 

 of fissures produced. In the Joplin district, where flint rock so abounds, 

 its exceeding brittleness caused the production of the greatest number 

 of small fissures and the smallest number of large ones. This, together 

 with the extensive interbedding of limestone and flint, with the lime- 

 stone largely removed by solution, leaving residual flint masses, has 

 produced most favorable conditions for ore deposition, and hence such 

 exceptionally rich bodies of lead and zinc ores in the district. 



The age of the geologic formations concerned is of no consequence, 

 excepting as that may have influenced their ability to withstand strains 

 and their tendency to fracture. Therefore the presence of ore bodies in 

 the Silurian of Madison county, Missouri, implies nothing either for or 

 against the presence of like ore bodies in the Silurian rocks of other 

 localities ; nor do the rich lead and zinc mines of Galena and Joplin in 

 the sub-Carboniferous rocks have any bearing on the probable presence 

 of like ore bodies in rocks of the same age in Iowa, Illinois, and other 

 States. 



Future mining developments will probably be confined principally to 

 the border areas of the elliptical uplift, a conclusion to be considered by 

 prospectors ; yet under most favorable conditions in the character of the 

 rocks valuable ore bodies may occasionally be found far up toward the 

 summit of the dome or equally removed from the border areas in oppo- 

 site directions, due to exceptional Assuring in such localities. 



Resume 



The Ozark uplift is elliptical in outline, and occupies the greater part 

 of southern Missouri and small portions of Kansas and Arkansas, The 



XXXV— Bull, Geol. Soc, Am., Vol, 11, 1899 



