116 THE ECONOMIC KESOUHCES OF ST. MARYS COUNTY 



these lenses are of small extent but some are sufSciently thick and 

 extensive to be worked, although in places they contain considerable 

 voj^etable material which renders them less serviceable. 



The cla_ys of the Wicomico formation closely resemble those of the 

 Sunderland both in general character and mode of occurrence. The 

 surface loams in many places are suitable for the manufacture of a fair 

 quality of brick, although they have never been used for that purpose 

 in the county. Elsewhere in the State and in adjoining States extensive 

 brick plants obtain their material from the surface clay loam of the 

 Wicomico formation. In a general way the areas of Sassafras loam shown 

 on the soil map of the county approximately represent the development 

 of the Wicomico surface loams. It must be borne in mind, however, 

 that a soil map and a geological map are constructed on an entirely 

 different basis and seldom do the lines defining the areas of certain soils 

 coincide with the boundary lines of the geological formations. Some 

 small portions of the Sassafras loam are of Sunderland age and some 

 belong to the Miocene yet the greater part represents the Wicomico 

 surface loam. Further small portions of the Wicomico surface loam 

 are mapped as meadow soils on the soil map. The clay lenses of the 

 Wicomico which resemble those of the Sunderland are not extensive 

 enough to be of any particular importance. 



The loam cap of the Talbot is more persistent than is that of the 

 Wicomico and Sunderland formations, and is almost co-extensive with the 

 distribution of the Talbot formation in this county. Just across the 

 Patuxent Eiver, in Calvert County, near Solomon's Island, brick was 

 formerly made from the Talbot clay loam. In St. Mary's County these 

 Talbot loam areas are most extensive along the Potomac Eiver, where 

 they cover the low, flat divides between the tributary streams. With 

 the exception of the valleys of the smaller streams the meadow soil 

 areas of the soil map approximately coincide with the distribution of 

 the Talbot surface clay loam. As has been demonstrated by the brick 

 plant in Calvert County, the Talbot loam produces a fair quality of 

 brick. 



Beside the surface loam of the Talbot, there are several other deposits 



