MARYLAND GEOLOGICAL SURVEY 115 



elevation whatever. An average of these averages indicates a slope be- 

 tween all the stations of 1.5 feet per mile. The general incline toward 

 the southeast, or toward the ocean and the lower portions of the Bay, is 

 indicated by the difference in elevation between the stations of Olivet and 

 Eidge and the rest of the stations. In addition to this it may be said 

 that any number of stations could have been chosen to show that the 

 Sunderland formation slopes away from the scarp-line toward the sur- 

 rounding waters. 



Not only does this surface show a decline in altitude from the foot of 

 the Piedmont Plateau to Point Lookout, but also it slopes from the water 

 sheds of the peninsulas of southern Maryland toward Chesapeake Bay 

 on one hand and the estuaries of the Potomac and Patuxent rivers on 

 the other. 



As the presence of a scarp has already been indicated, it need not be 

 discussed further, but a few words may be said in regard to the datum- 

 line. It has just been said that eight stations are located at this datum- 

 line. Many of these, which are separated by long distances, are at the 

 same elevation, while others do not depart widely from the general aver- 

 age. These differences in elevation are probably in part due to the per- 

 sonal equation of the various topographers who located the contours on 

 which the maps are platted, as well as to the differences in judgment 

 among field assistants in locating the separating line between the scarp 

 and terrace. Subsequent deformation has also doubtless somewhat 

 changed these elevations. 



No one will probably challenge the statement that the outliers sepa- 

 rated by scarps from the Lafayette formation above and the Wicomico 

 below, are all parts of the Sunderland and were originally connected with 

 the main body of the formation in southern Maryland. 



An examination of Plate XXV brings out clearly the plain-like char- 

 acter of the Wicomico terrace. All the stations, with the exception of 

 West, are located on the datum-line where the Wicomico terrace abuts 

 against the Sunderland-Wicomico scarp. No slope between stations has 

 a greater average than 3 feet per mile and a larger number than in the 

 Sunderland terrace show no variation whatsoever. The majority of the 



