ROAD MATERIALS. 9 



stones of the older formations. The best of these sands which 

 have yet come into use are obtained by crushing the friable 

 sandstones of the older formations, especially of the Lower 

 Carboniferous (Oxmoor) division. The material for the glass 

 works at Gate City, analyzing 99 per cent silica is from this 

 source, the rock being almost at the door of the works. 



Sandstones of the Coal Measures and of the Weisner for- 

 mation are also in places suitable, and in the Tuscaloosa divis- 

 ion of the Lower Cretaceous, we also have an unlimited source 

 of sands of every grade. 



In the upper of the Cretaceous divisions, viz., the Ripley, 

 there are numerous beds of excellent sands, some quite suitable 

 for glass making e. g. from the vicinity of Linden in Marengo 

 county. 



So also in the Tertiary formation we find numerous beds 

 of fine sands, such as occur for instance in the vicinity of Gas- 

 ton in Sumter county, and further south, in the territory cover- 

 ed by the Grand Gulf formation, are extensive beds of all 

 grades, in Washington, Mobile, Baldwin, Escambia, Coving- 

 ton, Geneva, Dale, Henry, Houston, etc. Travellers in that 

 section do not need to be reminded of the prevalence of sand 

 there. The Lafayette formation lastly, which mantles the entire 

 coastal Plain is prevalently a sand and pebble formation ; the 

 sands being as a rule, ferruginous, but in many places quite 

 suitable for building purposes. 



Road and Ballast Materials. 



The materials used in road making in Alabama are chert, 

 quartz pebbles, and limestone, including dolomite. 



The chert has probably been used more extensively than 

 either of the others. It occurs in the Lower Carboniferous for- 

 mation and in the Knox Dolomite of the Silurian. In the for- 

 mer it is generally in more or less regular beds or sheets, in 

 the latter rather in the form of concretionary masses. The 

 chert from both these sources has found extended use in several 

 counties especially Jefferson, Calhoun, Talladega. That from 

 the Lower Carboniferous formation contains a good proportion 

 of carbonate of lime, and shows a tendency to harden on the 

 surface, thus making an ideal road material. Extensive quar- 

 ries are near Birmingham, Leeds, Anniston, Jacksonville, and 

 other cities. 

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