32 RESOURCES OF TENNESSEE. 



If on the other hand, the advances and withdrawals of the 

 sea were due to changes in the sea level, the rocks of the area 

 would not be flexed, for they would have been left quiet through 

 the changes in geography. 



Such anticlines and synclines as may exist probably had their 

 inception during the elevation that followed the Lower Creta- 

 ceous deposition, and were enlarged during those that followed 

 the close of the Upper Cretaceous and the Tertiary. For it is a 

 principle of geology pretty well established that a fold begin- 

 ning in any period of movement is intensified during subse- 

 quent similiar movements. High folds with strong dips can 

 not be expected in the Reelfoot Lake district, or elsewhere in 

 the Embayment area. The anticlines, if they exist, are low and 

 flat. 



The formations of the Embayment area that may contain oil 

 and gas are covered with more recent ones, so that it is very 

 difficult to locate such folds as may exist without many more 

 deep well records than are now to be had. In fact with our 

 present knowledge, the location of the folds and consequently 

 of promising well sites, seems impossible except perhaps in 

 limited areas. The only criteria in conjecturing their shape is 

 in the structure of the older rocks surrounding the Embayment 

 area. In those along and east of the Tennessee River in 

 Tennessee and in those bordering the Embayment area in 

 Kentucky, Illinois, Missouri and northeastern Arkansas, the 

 folds are not in elongated anticlines and synclines, but are 

 more nearly in the shape of domes and intervening basins. In 

 central and southwestern Arkansas, the folds in the old rocks 

 west of the Embayment are distinct east and west anticlines 

 and synclines. 



With these facts in mind, the geologist in directing pioneer 

 oil and gas prospecting in the Embayment would proceed on 

 the hypothesis that the folding in the area being drilled would 

 be similiar in shape to that of the nearest old rocks on the 

 border. The floor of the Embayment area is the continuation 

 of these old rocks and their structure probably was transmitted 

 to the new ones above, in times of its oscillation. 



