210 On tfie Natural History of North America. 



Mines of various kinds are very abundant in the United 

 States. We are extremely rich in iron, copper, and lead. 

 The iron mines of Pennsylvania are, perhaps, inexhaustible. 

 Prodigious quantities of copper, nearly in a native state, 

 have been discovered near Lake Superior. A bed of cin- 

 nabar has been discovered in Virginia; and several veins of 

 plumbago have been detected in Pennsylvania and other 

 parts of the Union. As to gold and silver, these, as yet, 

 are principally to be found in the fields that are cultivated 

 by the virtuous hand of agriculture. Our country is ex- 

 tremely rich in coal. This useful article has hitherto been 

 found in the greatest abundance in the western parts of the 

 United States, beyond the Alleghancy mountains. It is iu 

 this same part of the continent that the principal salt springs, 

 and mines of sal-gem or rock-salt, are found. In a few years 

 we shall, in all probability, be able to do without the salt 

 of Europe. Hitherto very little sal-gem has been detected 

 within the limits of the United States. I am not, indeed, 

 certain that any has been detected. It must, however, 

 abound at no great distance from the immense salt springs, 

 which are now found in so many parts of our country. Of 

 sal-gem, however, prodigious quantities have been disco- 

 vered in the country that is watered by some of the branches 

 of the Missouri, west of the Mississippi *. 



I have lately returned from a three months tour (which 

 had been principally undertaken for the recovery of my 

 health) through the western parts of Virginia. I have visited 

 many of the most interesting natural objects in that part of 

 the United States, and have brought home a very considera- 

 ble collection of vegetables. In travelling over some of the 

 principal ranges of our mountains, particularly the Blue 

 Ridge and the North Mountain, I have not observed that 

 any of them are purely granitical. The stone composing 

 these mountains is, indeed, various ', but I think the pre- 

 dominant species is a petro-silcx, of diflerent degrees of. 

 hardness. Veins of schistus are sometimes found upon 

 some parts of these mountains 5 but such veins are princi- 

 pally abundant about tlreir bases. I have paid particular 

 attention to the declivities of the mountains. These I find 

 to be much less regiilar than Mr. Kirwan's ingenious ob- 

 servations (concerning mountains in general) would lead us 



* Since writing; tne abo^e, I have learned that very large quantities of sul- 

 phate of magnesia, or Epsom salt, have been discovered in some of the cal- 

 careous caves in the western pirts of Virginia. It is also said that the borate 

 of soda, or common borax, has been found in others of these caves. But this 

 last report requires further confirmation. 



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