504 W. B. Clark — Brandywine Formation of the 



gravelly types. The "Windsor sands, the next most important 

 soil type found in the Brandywine formation, consists of a 

 medium to coarse sandy soil that generally contains about 10 

 per cent of fine gravel. The soil is loose and friable and 

 reaches to a depth of about 8 or 10 inches and is underlain by 

 a coarse sandy subsoil. It is quite widely extended but is most 

 common in the area midway between the landward and sea- 

 ward borders. The Norfolk sand is less widely extended in 

 the Brandywine formation than the two preceding soils and 

 consists of a medium to coarse orange or yellow sand to a depth 

 of about 10 inches and is underlain by a coarse sandy subsoil 

 which usually becomes loamy at a depth of about 3 feet. 



Vegetation and culture. — Extensive areas are covei'ed with 

 scrub pine and culled hardwoods of various types, the scrub 

 pine being found largely growing on the Windsor sand. Large 

 areas, however, are under cultivation. The Leonardtown 

 loam, because it is capable of retaining a considerable amount 

 of moisture during the entire growing season, is well adapted 

 to growing grass, wheat, and corn where general farming is 

 practised, and to cabbages, cucumbers, and late strawberries in 

 the trucking areas. It is only producing, however, to its full 

 capacity in the northern part of the count}', where the soil has 

 been extensively enriched and where a ready market for its 

 products has been found in Washington. The Windsor sand 

 is very porous but is well adapted to early truck crops, early 

 peaches, and under certain conditions to fine grades of tobacco. 

 Its loose, porous character makes it particularly hard to manage 

 during a protracted drought and for this reason intensive cul- 

 tivation is required including the incorporation of considerable 

 amounts of organic material. The Norfolk sand, although 

 very porous, has been utilized in general farming and truck 

 growing and is well adapted for early strawberries, melons, 

 sweet potatoes, and small crops of high grade tobacco. 



Stratiyraphic relations of the deposits. — The Brandywine 

 formation overlies all of the older Coastal Plain formations of 

 Tertiary and Cretaceous age unconformably and at a few points 

 rests on the crystalline rocks of the Piedmont. It is separated 

 from the next younger or Sunderland formation throughout 

 much of the region by a clearly marked escarpment, the 

 Sunderland formation wrapping at a lower elevation about the 

 lower margin of the formation unconformably and filling the 

 pre-Sunderland valleys. 



One of the most striking physiographic features of the 

 region is the Sunderland plain extending into the pre-Sunder- 

 laud valleys and abutting against their irregular slopes. 

 Streams are often absent today in these old valley lines but 

 where present have cut irregular channels through the surface 



