Red Sand Stone formation of North-Carolina. 175 
Uses.—Though the colour of the mineral is blue or 
bluish grey, the fragments which have for some time been 
exposed to air and light, assume an appearance in some 
degree resembling common borax. ‘This induced Mr. 
Elias Baldwin, of the Society of Friends, an imgenious 
smith, to make an experiment with it in brazing, asa sub- 
stitute for borax. His success encouraged him to apply it 
in various ways, until he found it to be the best flux ever 
used in brazing and welding. 
By using it pulverized as a substitute for clay, he welded 
the most refractory steel with the same facility as if it were 
the softest of iron. He performed also the process of bra~ 
zing several times, by which he proved its very great supe- 
tiority to borax in two respects; its requiring a much 
smaller quantity, and its remaining more fixed in a high 
heat.” 
14. Red Sand Stone formation of North- Carolina. 
Extract of a letter from Professor D. OtmstTEanp, of the 
College at Chapel-Hull, North-Carolina, dated Feb. 26, 
1820. 
An extensive secondary formation has lately been discov- 
ered very near us. On the road between this place and 
Raleigh, travelling eastward, we come to it four miles from 
the College ; but at another point it has been discovered 
within two miles of us. It is a sand stone formation. The 
varieties are the red and grey. I have traced it through the 
counties of Orange and Chatham, and have ascertained its 
breadth, between this and Raleigh, to be about seven miles. 
Its direction is a little west of south. If a line be drawn 
through the Richmond bason parallel to the great moun- 
tains west of us, it will pass through this formation. Hence, 
must we not regard this as a continuation of the great sand 
stone formation, which W. McClure has traced to the Rap- 
pahannock? Must we not consider the Richmond bason 
and this as forming parts of the same formation? ‘The va- 
riety found nearest to this place is not unlike the old red 
sand stone found in your vicinity. 
It was natural to look for coal here, and I have for some 
time directed the attention of my pupils, and of stone-cut- 
