168 THE COASTAL PLAIN FORMATIONS OF CECIL COUNTY 



represented on the hilltops indicated on the map from the abundance 

 of gravel in those localities. Most of the deposits of Lafayette on 

 Elk Xeck are characterized by indurated blocks of conglomerate, 

 ranging from cobbles up to masses a foot in thickness and weighing 

 several hundred pounds. These have evidently broken away from 

 more or less continuous bands of conglomerate, which formerly ex- 

 tended over the summit region of Elk Neck, and although obscured at 

 the present time, no doubt still exist on many of the hilltops. 



The thickness of the Lafayette formation is a matter difficult to 

 determine. Not only is it impossible at all times to ascertain the 

 location of the contact between the base of the Lafayette and the 

 formation on which it rests, but the slight irregularities in the con- 

 tact indicate that the formation is in the nature of a cover or veneer, 

 and to assume that its base has the same altitude in the center of the 

 hill which it has on the sides would seem perhaps to be somewhat ven- 

 turesome and unwarranted. There cannot, however, be a great dif- 

 ference between the two. If the topography of Bull Mountain is 

 correct the thickness of the Lafayette in that locality is a hundred 

 feet, and the same is true of Black Hill and the large area to the 

 southeast. The gravel cappings of the Hog Hills are not quite so 

 thick, and the areas of the Piedmont Plateau do not range much above 

 40 feet in thickness, and probably do not average even that amount. 

 It is possible that the elevations of Bull Mountain and Black Hill 

 have not been accurately determined, and that the base of the La- 

 fayette formation in these two localities is also somewhat incorrect, 

 in which case the thickness of the formation would be reduced. In 

 the absence, however, of absolute knowledge on this point it is safe 

 to say that the Lafayette in Cecil county is often very thin, and 

 never exceeds 100 feet in thickness. The maximum thickness lies 

 somewhere between 80 and 100 feet. The strike of the Lafayette 

 gravels is like that of the other Coastal Plain formations, from north- 

 east to southwest. The dip of the formation is to the southeast, but 

 its amount is difficult if not impossible to determine accurately. 

 There is no doubt that the general base of the formation on Elk Neck 

 is considerably lower than that of the same formation on the Pied- 



