88 The American Geoloiji.sf. February, 189") 
events took place, shuihir to those immediately preceding the 
deposition of the Lower Carboniferous rocks. The waters 
again crept inland and upland, availing themselves of the 
products of sub-aerial decay for the making of new sediments, 
such as shales, sandstones, and chert conglomerates or boulder 
beds. These soon filled the depressions and spread themselves 
over the surface. The submergence probably did not extend 
so far inland as that of the Lower Carboniferous epoch. It 
was doubtless, however, well beyond the present Coal Measure 
margin. Outliers and coal pockets in the interior counties 
indicate a wide extension, but some of these could have been, 
and probably were, formed in inland lagoons. That they are 
sometimes surrounded by Silurian rocks shows that Lower 
Carboniferous or other intervening strata, if ever present at 
such points, had been removed prior to the Coal Measure dep- 
osition. This epoch, though one of fluctuating movements, 
was, on the whole, characterized by a sinking of the area sur- 
rounding the Ozark uplift. A reversal of the movement, in- 
augurated the Mesozoic. 
The Mesozoic Era. — With this era we have little to do. No 
rocks of this formation are represented in the state. At the 
beginning, all of Missouri was above sea level for the first 
time and has continued so ever since, with the exception of 
the Mississippi embay raent. This era is noteworthy, how- 
ever, as marking the beginning of the present drainage sys- 
tem of the state. Heretofore, during various uplifts, a radial 
drainage from the center of the dome was undoubtedly de- 
veloped, to be obliterated with each succeeding submergence. 
With the post-Carboniferous uplift, the Mississippi valley was 
first defined, as a result of the Cincinnati and Ozark uplifts: 
while the Missouri river valley appeared as the result of these 
and of the Wisconsin uplift. The present drainage began 
-with a radial flow of water from the center of the Ozarks. 
Traces of this are still seen in the distribution of the streams 
of that area. At the beginning, the Missouri river was prob- 
ably only rudimentary, its head being within, or at least not 
very far beyond, the western border of the state. This was 
«o, because a divide must have existed in western Missouri or 
eastern Kansas, beyond which the waters flowed westward into 
the Mesozoic seas. 
