Mathews — Structure of the Piedmont Plateau. 153 



that the lines here indicated represent the structural character- 

 istics up to the scale of the base employed. The individual 

 axes distinguished in the area are described in greater detail in 

 the following discussion. 



2 



Structure Lines of the Piedmont. 



East Alexandria- Winters Pun Syncline. — Poorly exposed 

 syncline extending from Churchville to east of Baltimore, east 

 of Washington to Alexandria. Covered for the most part 

 with Coastal Plain deposits and largely hypothetical. As 

 shown in Harford county, this axis is plunging southwest. 



Washington Uplift-Toioson-Belair Anticline — A rather 

 shallow anticlinal axis which may in reality be composed of 

 several minor ones, recognized by Keith as a portion of his West 

 Washington anticlinorium. Occupied for the most part by gab- 

 bro sheets on either flank. Probably the line passing from the 

 vicinity of Belair eastward through the central Piedmont dis- 

 trict of Cecil county and possibly corresponding to the eastern 

 anticlinal axis suggested by the older gneiss of the Philadelphia 



* When the terms "anticlinal axis" and "synclinal axis" are used it is not 

 intended to convey the idea that the lines are of simple structural folds 

 but that these lines represent the dominant axes of anticlinoria and synclinoria. 

 For local points see maps of National and State Geological Surveys. 



