SOILS OF THE SASSAFRAS SERIES. 15 



which' is characteristic of this formation east of the Chesapeake Bay. 

 The chief areas of the Sassafras silt loam found in southern Mary- 

 land occur upon its surface. 



The highest Pleistocene terrace in southern Maryland is called the 

 Sunderland formation. It occupies a large part of the broad, nearly 

 flat interstream areas, especially along the Chesapeake Bay and the 

 lower reaches of the Potomac River. It is in reality a gently sloping 

 plain which has been dissected into broad, irregular plateaus, sepa- 

 rated by the present tidewater estuaries. 



A considerable proportion of the area of the Sunderland formation 

 in southern Maryland consists of materials that do not give rise to 

 soils of the Sassafras series. The heavy, silty soil of gray color which 

 predominates on the plateau surface is. classed as the Leonardtown 

 loam. Upon somewhat more rolling surfaces and along certain of 

 the uplands there are found soft sandy loams and fine sands derived 

 from this formation and formed by its partial erosion and mingling 

 with underlying materials which have been correlated as the Sassa- 

 fras sand, fine sand, fine sandy loam, and loam. These areas are of 

 somewhat mixed origin, but owe their chief characteristics to the 

 influence of the material derived from the Sunderland formation. 



A large area in the northern part of southern Maryland is occupied 

 by the highest Coastal Plain terrace, referred to the Lafayette forma- 

 tion, and by the exposed outcrops of some of the older Coastal Plain 

 strata. None of these give rise to soils of the Sassafras series. 



All the occurrences of the soil of the Sassafras series in southern 

 Maryland are confined to the areas of the Pleistocene terraces, except 

 where erosion has partially removed these formations and mingled 

 their remnants with older materials. The largest areas of the soils 

 of this series are found along the upper waters of Chesapeake Bay 

 and along the forelands which border the principal estuarine rivers, 

 particularly the Potomac. Only the better-drained areas of these 

 terraces give rise to soils of this series. 



Examinations of the soil materials of the region south of the 

 Potomac River show that the Potomac and the Rappahannock Rivers 

 are discontinuously bordered by the lowest terrace, known as the 

 Talbot formation x in Maryland. It is also evident that the Wicomico 

 terrace is represented at intermediate elevations and that the rolling 

 or flat-topped interstream areas belong in part to the Lafayette 

 formation. 



These different formations are closely related to the similar occur- 

 rences in southern Maryland, and soils referable to the Sassafras 

 series occur to a limited extent along the low forelands upon the lower 

 courses of the rivers. Considerable areas of the Sassafras loam and 



1 See Nomini and Fredericksburg folios, U. S. Geol. Survey, and Bui. IV, Virginia Geol. 

 Survey, Physiography and Geology of the Coastal Plain Province of Virginia. 



