348 CONTRIBUTIONS TO THE GEOLOGY OF 



Topographical Features. 



The general aspect of the peninsula, and more especially of the four 

 eastern counties, is that of a nearly level plane, maintaining an average 

 elevation of from sixty to seventy feet above the tide. This plane, 

 gently furrowed by numerous ravines, subordinate to the creeks and 

 inlets indenting the peninsula, frequently subsides to a lower level, in 

 approaching the rivers on either side. The wide bench thus formed, 

 sometimes extends in a direction parallel to the river for a distance of 

 several miles, presenting an unvarying uniformity of elevation, and 

 reaching nearly to the water's edge. A third, and lower plane fre- 

 quently intervenes between the river bank and the table land above 

 described, but in many cases this terraced configuration of the surface 

 is not observed, and the high and precipitous cliffs w'hich rise very 

 near the water's edge, retain the general level of the inland portion of 

 the peninsula. Although the usual elevation of this district is such as 

 above described, at several points a far higher level is attained. The 

 ridge which forms the water shed of the streams flowing into the Po- 

 tomac and Rappahannock, approaching very near to the former, con- 

 stitutes, in some places, the river bank. At these points it attains an 

 unusual elevation, towering, as at Stratford and Chantilly, to a height 

 of about one hundred feet above the water's edge, and affording from 

 its summit an extensive and enchanting view of the noble river which 

 laves its base, of the cultivated farms around, and of the cliffs on the 

 opposite, or Maryland side of the Potomac. At Sprize Hill, about four 

 and a half miles from Smith's Point, the ridge bends round to the 

 south, and continues for some distance in a direction across the penin- 

 sula, preserving an elevation of about sixty feet. Its declivity on the 

 east forms an abrupt termination of the higher level of the neck, be- 

 tween which and the bay shore is an extensive flat, of from two to 

 four miles in width, rarely rising beyond the height of ten feet above 

 the level of the tide, and in some places so low as to be occasionally 

 overflowed. 



The western portion of the peninsula, though still, in the main, pre- 

 senting a similar uniformity of surface, is somewhat more abruptly fur- 

 rowed. This inequality, increasing as we proceed further to the west, 



