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AVAILABLE LIMESTONES. 



General geology. In northern Alabama the combined effects 

 of geologic structure and erosion have resulted in certain defi- 

 nite topographic types, with which the geologic outcrops are 

 closely connected. 



Structurally northern Alabama is made up of a series of paral- 

 lel synclines and anticlines, trending usually a little north of east. 

 The anticlines are sharp, narrow folds; the synclines are flat, 

 wide basins. The effect of erosion has been to cut away the 

 anticlines and the streams of the region now run along anticlinal 

 valleys bordered by flat-topped synclinal plateaus. 



The plateaus throughout most of northern Alabama are 

 capped by conglomerates, shales, and sandstones of the Coal 

 Measures. The lower Carboniferous limestones 'commonly 

 outcrop along the sides and at the immediate base of the 

 plateaus. The lower Silurian beds occur as long, narrow out- 

 crops in the valleys. The middle of the valley is usually occu- 

 pied by Cambrian shales and the Knox dolomite. The Tren- 

 ton limestones would normally outcrop as two parallel bands in 

 each valley between the middle of the valley and the foothills 

 of the plateaus. Faulting has, however, been so common that 

 only one of these bands is usually present, the other being cut 

 out by a fault. 



Lower Carboniferous. Limestones of suitable quality for 

 cement manufacture occur in the Mountain limestone or Ches- 

 ter formation of the lower Carboniferous. Perhaps the most 

 accessible occurrences of this rock are in the Tennessee Valley 

 to the west of Tuscumbia and south of the river and railroad. 

 Here the quarries of Fossick & Co. were formerly located. 

 Their quarries at this time are farther eastward, but at a greater 

 distance from the river, in Lawrence county north of Russell- 

 ville. This outcrop extends thence eastward along the base 

 of Little Mountain as far as Whitesburg, above which place 

 to Guntersville the river flows through a valley floored with 

 lower Carboniferous limestone. The Southern Railway passes 

 over outcrops of this rock in most of the mountain coves east 

 of Huntsville, and from Scottsboro to the Tenneissee line the 

 country rock is almost entirely of this formation. The Louis- 

 ville and Nashville Railroad south of Decatur nearly to Wilhite 

 is mostly in the same formation. These two lines, together 



