MURPHREE'S VALLEY; INDUSTRIAL MATERIALS. 125 



enough cement to hold it firmly together, but is not filled 

 with it, like most of the conglomerates of the Coal Measures. 

 The rock appears to be mainly silica, with some alumina. 

 The same materials of which fire bricks are made. In addi- 

 tion to this its mechanical structure renders it highly re- 

 fractory. No fire test to which it has yet been subjected, 

 affects its structure. At a white heat in a furnace, it neither 

 melts nor decrepitates. 



As these qualities of this rock have not hitherto^ been 

 known, and are here only suggestively presented, it would 

 be premature to decide definitely on its merits. They are 

 however believed to be worthy of immediate and thorough 

 testing. If this rock will fully answer the purpose for which 

 fire bricks are now used, it will be much cheaper, and supply 

 a want that has long been felt in this region. The rock is 

 generally very accessible, very abundant, and having no 

 cleavage planes, can be easily worked into any desired size 

 or form. 



A material sufficiently refractory, strong and durable for 

 hearths, and lining of furnaces, is the only thing necessary in 

 the manufacture of iron which this region has not hitherto 

 supplied. Wide and persistent search among the clays has 

 been made without satisfactory results. Perhaps among the 

 rocks the "missing link" may be found, which will give to 

 this region the full complement of necessary iron and steel 

 making materials. 



NOTE. Years ago Mr. James Thomas informed the writer that the most 

 satisfactory hearth for the Oxmoore Furnaces was a conglomerate rock. 

 It has since been ascertained that this ^vas the rock used there by him. It 

 is classed by Mr. Hayes, U. S. G. Survey, as "The Birmingham Breccia." 



