MARYLAND GEOLOGICAL SURVEY 233 



and the people are in a generally prosperous condition. Some of the 

 best improved farms of the county are located within the limits of this 

 soil formation. 



CECIL CLAY. 



This formation, like the one just described, is found in the Pied- 

 mont Plateau region of Cecil county. The formation occurs in sev- 

 eral areas scattered over the northern half of Cecil county. There 

 are 11 of these areas, but the largest and most important are situated 

 in the extreme northern part. The surface of the Cecil clay is prob- 

 ably more rough and broken than the Cecil loam, although there are 

 some areas where the gently rolling character of the country is a rule. 

 The broken and hilly areas of this formation are along the Susque- 

 hanna river and the Octoraro and Conowingo creeks. A few of the 

 smaller areas of this formation form prominent hills in the Coastal 

 Plain part of the county. Doubtless these hills were once covered 

 by the gravels which cap the surrounding hills, but subsequent erosion 

 has removed this coating and they are now isolated areas entirely 

 surrounded by the unconsolidated sands, gravels and clays of the 

 Coastal Plain. Grays Hill, 2 miles northeast of Elkton, furnishes 

 a striking example of the isolated occurrence of this formation. This 

 hill rises considerably over 150 feet above the surrounding country, 

 which consists of broad terraces and low, marshy areas characteristic 

 of this section of the Coastal Plain country. Plate XXI, Fig. 1, 

 shows clearly the relations of Grays Hill to the surrounding country. 



These soils are also residual, being derived from the rocks which 

 underlie them. The Cecil clay is for the most part derived from the 

 weathering of the hard, igneous rocks, such as gabbro and meta-gabbro. 

 These are dark-colored rocks, which weather comparatively slowly 

 into characteristic spheroidal masses. These large, rounded boulders 

 are thickly scattered over the surface in some places in the Cecil clay. 

 These stony areas are quite abundant on the upland just east of the 

 Susquehanna river. Here the boulders are so thickly strewn over 

 the ground that fields of several acres are often uncultivated on 

 account of them. They vary from a few inches to many feet in 

 diameter and are often spoken of as " niggerheads." 





