84 OC. A. Goessmann on the Chemistry of Common Salt. 
or blue, rarely green. Its most frequent saline admixtures are 
1st, sulphate of lime, the chlorids of calcium, magnesium, and 
otassium, and the bromid and iodid of magnesium ; or 2d, the 
sulphates of lime, magnesia, and soda, the chlorid, bromid, ‘and 
iodid of magnesium, etc. rock salt, which contains more 
than from 2 to 3 per cent of these impurities is unfit for domestic 
uses ; and a salt which contains carbonate, nitrate or borate of 
soda, or similar foreign substances is, especially in its natural 
ei poquently. unfit even for many manufacturing purposes 
very great de ee if wo i: at all, are hao dissolved, and 
their solutions treated like brines. 
The northern part of this continent contains numerous salt 
leposits ; some quite recently discovered, like that upon Petit 
Anse Island, Vermilion Bay, Louisiana, the one in Canada 
West, at Goderich on the shores of Lake Huron, and also that of 
na and Nevada. The salt deposit at Goderich is buried in the 
shales of the upper Silurian vee Hunt), ata depth of from 
eight to nine hundred feet; it is about forty feet thick, covers 
so far as eat indications show, dozens of square miles, an 
is in close proximity to Lake Huron; its solution furnishes the 
superior brines at Goderich.* The salt deposit of Petit Anse 
Louisiana, is apparently imbedded in Quaternary formations e 
W. Hilgard), and is covered merely by a diluyial drift from 
to 18 feet in thickness ; its extent is unknown, having been ut 
persally explored. It is accessible by sea and by land, and is 
_ within 275 miles of the mouth of the Mississippi river. This 
- Petit Anse rock salt, so far as at present ak oon of the 
mana aya 28, Sony 
See: 
si 
