118 THE ECOXOMIC RESOURCES OF ST. ilAEYS COUNTY 



Sands of this character possess a distinct value for road-making pur- 

 poses, as they pack readily and make a firm road bed. Where the 

 material can be easily obtained in large quantities good roads of this 

 kind can be very economically constructed. The ferruginous sands are 

 best developed in the Sunderland formation, principally because of the 

 greater age of the deposits, although also represented in the Wicomico 

 and the Talbot. 



THE GRAVELS. 



The Pleistocene formations contain numerous beds of gravel widely 

 distributed throughout the region. They occur in pockets or lenses, 

 either immediately at the surface or but thinly covered by the sands and 

 loam. In the latter case they can be seen in many places outcropping 

 along the valleys. These gravel deposits have only been used to a small 

 extent in this section although similar deiDosits in the vicinity of Wash- 

 ington have been extensively worked. As ballast for roads they possess 

 considerable value and will doubtless be extensively used in the future 

 in the building of permanent roads throughout the county. They are 

 probably inferior in value to the igneous rocks yet serve their purpose 

 well when properly used. They are generally rich in iron, which acts 

 as a cementing agent, although there are many places where the gravels 

 lack this desirable material. In such cases it is necessary to add ferru- 

 ginous sand or clay to l)ind them together. The gravels range in size_ 

 from coarse sand to pebbles several inches in diameter. They are 

 especially well developed at the base of the Sunderland formation and 

 are exposed in almost every place where streams have cut through the 

 overlying loam and sand. Many of these outcrops of Sunderland gravels 

 are represented in the soil map as the Susquehanna Gravel areas. 



THE BUILDING STONE. 



Although the formations of the county are composed almost entirely 

 of unconsolidated materials, yet locally indurated beds are not uncom- 

 mon. In the absence of any better stone these indurated ledges furnish 

 considerable material for the construction of foundations and well walls. 



