78 THE PHYSIOGRAPHY OF CECIL COUNTY 



THE RECENT STAGE. 



The time which elapsed during the deposition of the Talbot forma- 

 tion was probably much shorter than that occupied by any previous 

 epoch. The land again rose to a position higher than that occupied 

 today, and Chesapeake Bay and its system of estuaries shrank con- 

 siderably beneath their present dimensions. This stage is illustrated 

 approximately by the present shore-line. Since that time the region 

 has once more started in a downward direction, and little by little 

 is sinking beneath the waters of the Atlantic Ocean and of Chesa- 

 peake Bay. The movement is exceedingly slow and only appreciable 

 to one who is trained to compare phenomena which are years in 

 their execution. Cecil county is, therefore, at the present time under- 

 going another period of partial subsidence and deposition. 



The Origin of the Streams of the Piedmont Plateau. 



Of the streams which cross the Piedmont Plateau of Cecil county, 

 Conowingo, Octoraro, Principio, Northeast and Big and Little Elk 

 creeks are the most important. These streams have three important 

 characteristics in common: first, they flow in deep, narrow gorges 

 throughout the lower portions of their courses, while their head 

 waters descend little, if any, below the general level of the country. 

 This feature is best seen in Principio, Northeast and Big and Little 

 Elk creeks. These three streams are confined almost entirely to 

 the Piedmont Plateau of Cecil county, and the change from a bed 

 at the bottom of a deep gorge to one lying on the flat surface takes 

 place within a few miles. The case of Conowingo and Octoraro 

 creeks is somewhat different as these waters head well back in Penn- 

 sylvania. Their upper courses are not shown on the atlas of Cecil 

 county, but if the streams were followed backward far enough, they 

 too, would be seen to rise gradually from the bottoms of gorges to 

 the surface of the country. 



The second feature which the streams hold in common is that they 

 cross the Piedmont Plateau, not in short, direct courses, but in long, 

 winding channels. This meandering feature is best developed in 

 Octoraro Creek, although possessed to a certain extent by all the 



