28 MINERAL RESOURCES OP ALABAMA. 



Dolcito quarry, near Birmingham, is one of the largest in the 

 state, having a capacity of 2,000 tons a day. At the present 

 time it is some 300 yards* long and nearly 100 feet in depth at 

 the deepest part. It shows a number of ledges which carry less 

 than i per cent, of silica in car load lots. 



About one car load a day of selected lump from these ledges 

 is sent to the Ensley 'Steel Works to be used instead of mag- 

 nesite in the lining of the furnaces. 



The accompanying view, Plate IV, shows the condition of 

 this quarry in 1900. 



Other large quarries in the Dolomite are in the immediate 

 vicinity of North Birmingham. 



The dolomite from this formation is not used in lime burn- 

 ing though it would no doubt make an excellent lime, as is 

 shown by the lime made of a crystaline dolomite at the Che- 

 wacla lime works, in Lee county, near Opelika, where the do- 

 lomite of unknown geological age is associated with metamor- 

 phic rocks. 



Limestone. The most extensively quarried limestone is 

 that occurring in the Lower Carboniferous formation and gen- 

 erally known as the Mountain Limestone. In the northern 

 part of the state this rock is 350 to 1,300 feet in thickness, and 

 covers a great area. In the southeastern part of the region of 

 their occurrence these* limestones become very slaty and sandy. 



The purer portions of this limestone carry from 95 to 99 per 

 cent, carbonate of lime, but with the better quality of the rock, 

 shales are often interstratified and in the lower part of the for- 

 mation, the limestone is highly siliceous and of dark blue color. 



The Mountain Limestone, as the name indicates, often occurs 

 on mountain sides above drainage level, and therefore in posi- 

 tion admirably situated for extensive and cheap quarrying. 

 The principal quarries are near Blount Springs and Bangor on 

 the L. & N. railroad, and near Trussville and Vann's on the 

 A. G. S. railroad. 



The Trenton or Pelham Limestone of the Silurian is another 

 great limestone formation which has been much used both as 

 flux in the furnaces and in lime burning. This limestone oc- 

 curs in long narrow belts on the flanks of the Red Mountain 

 ridges on each side of the anticlinal valleys. Sometimes it lies 

 in the valley at the foot of the mountain, sometimes it occurs 



