THE BARITE DEPOSITS OF MISSOURI 49 



That the Mississippian and Pennsylvanian systems, especial- 

 ly the latter, were once over this area is doubtful. Since that 

 time the surface of the area has been exposed to erosion, save for 

 a few brief intervals. Possibly the Cretaceous sea came in from 

 the south, but if such was the case any deposits of that time have 

 been removed. Evidence has been cited above to show that no 

 great amount of movement occurred at the close of the Creta- 

 ceous period. Again it is very probable that during the Tertiary 

 there were some deposits in this region or to the south. The 

 Lafayette formation may have been the only formation of this 

 period, and its presence is conjectural. Even if once present, it 

 was a terrestrial deposit and does not represent a period of sub- 

 mergence. 



The area was probably subjected to its last uplift in late 

 Pliocene times and since then the erosive work of the streams 

 has been the dominant geological work going on, unless, as has 

 been suggested, there were movements in the Pleistocene. The 

 recent deposits along the streams are so insignificant as not to 

 merit mapping. 



GEOGRAPHY AND GEOLOGY OF THE CENTRAL DIS- 

 TRICT^ 



GEOGRAPHY 



The producing part of the Central district is located chiefly 

 in Morgan and Miller counties in the central part of the state, 

 but small deposits of barite are found in Moniteau and Cole 

 counties. It is reported that some barite is found in Camden 

 County south of the above area, but it is not of much importance. 



"The following notes on the geology and physiography are taken 

 from the following reports on the geology of Moniteau, Morgan and Mil- 

 ler Counties, to which the reader is referred for the more complete de- 

 scriptions of the areas : 

 Ball, S. H., and Smith, A. F., "Geology of Miller County, Missouri," Mo. 



Bur. of Geol. and Mines, vol. I. 1913. 

 Marbut, C. F., "Geology of Morgan County, Missouri," Mo. Bur. of Geol. 



and Mines, vol. VII. 1907. 

 Van Horn, F. B., "Geology of Moniteau County Missouri," Mo. Bur. of 



Geol. and Mines, vol. III. 1905. 



