12 KENTUCKY GEOLOGICAL SURVEY. 



stationary or even subsiding. There may have been times of 

 unrest, with intervals of comparative quiet interspersed." 



That the movement of uplift was a slow, gentle one may be 

 inferred from the almost horizontal character of the strata in all 

 the region controlled by the Cincinnati uplift. It was a move- 

 ment, or series of movements, probably the latter, unmarked by 

 any catastrophes at the time or later. Hence the conditions 

 were wanting which render possible the accumulation of valua- 

 ble ore deposits. This is true with few exceptions. Some fault- 

 ing in the Kentucky river region has permitted some vein for- 

 mation with barite deposits producing some lead and zinc. 



The oldest rocks which outcrop in Kentucky and Tennessee 

 are prevailingly limestone and give evidence of rather slow for- 

 mation in a clear inland sea extending from the Appalachians to 

 ^he Rockies. This sea has gradually filled up. The Cincinnati 

 island was the first large fill and served as a sort of nucleus, 

 around the sides of which later formations were laid down, de- 

 rived in part from the waste of its surface. From the earliest 

 times this was probably a shallow part of the sea with deeper 

 areas bordering it. 



The Lexington* shows more shale than the Stones river 

 or Highbridge. By the close of Lexington time, or 

 soon after, conditions had so changed that a very con- 

 siderable amount of mud was thrown into the sea. So 



2 Not all of these movements may have been actual movements of the 

 solid crust. It is still one of the moot questions in geology what part 

 of the oscillations of land surfaces, which play so large a part in geologic 

 history, has been an actual up and down movement of the solid crust, 

 if, indeed, one may speak of it as a solid crust involving a greater or 

 less areal extent, and what part may have been due to a shifting of the 

 waters on the surface of the earth heaped up in one (or more ?) places 

 and drained from the rest of the sphere's surface due to causes which 

 may be only surmised. 



Possibly also the actual amount of water in the seas may have varied, 

 perhaps at times increased by great volcanic eruptions, and at other times 

 diminished by absorption into rocks in the processes of crystallization. 

 Any change in sea level would produce an apparent elevation or subsidence 

 of land surfaces. Possibly also the amount of ground water has varied. 



3 For the relative position of these formations in the geological scale, 

 see the table of formations on page 13. 



