242 PHYSIOGRAPHY AND GEOLOGY OP THE COASTAL PLAIN PROVINCE. 



cene or Lafayette debris. Generally a gravel band is found at the base of 

 each of these formations, covered by a surface loam cap in which are 

 distributed scattered pebbles or pebble lenses. 



The Lafayette, in its most v/estern limits, is almost entirely composed 

 of the clay residuum of the crystalline rocks, and the Pleistocene deposits in 

 the extreme eastern portion of the State are often composed almost entirely 

 of fine sands but elsewhere these formations contain much gravel. The 

 gravel is more abundant in proximity to the larger streams and decreases 

 in amount and in size of the pebbles over the broader divides, yet removal of 

 the upper clay loams at some distance from the main streams will usually 

 reveal the presence of a gravel layer. 



Gravel pits are numerous although much less use has been made of the 

 deposits for road purposes than one would expect when it is everywhere 

 recognized that the heavy sandy roads have been serious drawbacks to the 

 development of the country in so many portions of the Virginia Coastal 

 Plain. The gravel is of very unequal value for road-building purposes, 

 depending primarily on the matrix in which the gravel occurs. Pure quartz 

 gravel in a matrix of loose sand will not pack of itself and is of little value 

 if spread on sandy roads. If spread over a clay road, however, it will become 

 mixed with the clay and eventually form a firm road bed. Id some places 

 the gravel occurs in a clay or ferruginous sand matrix and is then splen- 

 didly adapted for road-building purposes. By making several applications 

 of such gravels the worst' highwaA^s can eventually be converted into firm 

 roads both in dry and wet weather. 



The table below shows the details of the sand and gravel industry of the 

 Virginia Coastal Plain, and the comparative quantities and values in 

 1908 and 1909. 



Production of Sand and Gravel in Virginia Coastal Plain, 1908 and 1909, 



hy uses, in short tons. 



Sand — 



Glass 

 Molding 

 Building 

 Fire . . 

 Engine 

 Furnace 

 Other 

 Gravel . . . . 



Total 



1908 



Quantity 



41,900 

 103,936 



2,960 



4,712 



234,894 



388,402 



Value 



20,925 

 46,096 



2,554 



760 



24,154 



$94,489 



1909 



Quantity 



15,489 

 340,318 



1,526 

 1,379 



43,631 

 319,487 



721,830 



Value 



5 12.605 

 107,749 



220 



1,881 



6,349 



69,631 



$198,435 



These figures do not represent the total production of sand and gravel 

 in the Virginia Coastal Plain, as large quantities are produced and utilized 



