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CARBONIFEROUS SYSTEM. 161 
The industrial products of this system are numerous and important. 
We have coal of all kinds for household purposes and gas ; iron, sandstone, 
limestone, and fire-clay. From the shales are obtained alum and the 
remarkable paraffin oil; and so abundant in America and elsewhere is 

Fig. $6.—Carboniferous Plants. 
this ancient oil, that when the earth is bored, a flood of it issues forth 
yielding thousands of gallons daily. 
Organic Remains.—The organic remains found in this system are very 
abundant and remarkable. Plants are numerous, varied, and beautiful. 



Fig. 87.—Carboniferous Trees: 
1, Sigillaria; 2, Calamite; 3, Stigmaria; 4, Lepidadendron, 
Terns are found with the most perfect fronds, as distinctly traced upon 
the rock as a modern dried fern on the pages of a book. We find also 
large and beautiful club-mosses exquisitely exhibited. But the most 
luxuriant and beautiful of all are the great pine-like araucarias, the tree- 
ferns, and tall reeds that grew in boundless swamps and jungles along 
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