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Gypsum ; whether it is found in the United States? 

 By Richard Peters. 



Read April 12th, 1808. 

 Sir, 



In my communication upon the subject of gypsiiniy 

 1 mention, that "■! have not been able to discover any 

 quarries o^ gypsiwi, proper for husbandry, in this or any 

 other of the United States. There are, in a variety of 

 places, gypseous substances," and I may add, fibrous 

 gypsum. I beg this to be understood as confined to my 

 own knowledge ; without impeaching that of others. In 

 your publication, entitled ''''A Geological Account of the 

 United States^'''' page 408, several instances are men- 

 tioned of gypsum discovered in sundry places ; and the 

 authorities for the facts are cited. Specimens have 

 been, at diiferent periods, shewn to me, as being gyp- 

 sum, and great expectations were formed concerning 

 them. They for the most part turned out to be either 

 a species of r//a(^cw^cr ; or lime stone: or, if really gypsum, 

 not likely to be profitably used in agriculture. The 

 former is a gypseous substance, being composed of the 

 vitriolic acid and calcareous earth. But it is not the 

 gypsum which we find so pre-eminently useful. The 

 alabaster is found in this and other states, in many 

 places ; and has no doubt some properties promotive of 

 vegetation. But I have not made any experiments with 

 it. Some of it was discovered in digging the proposed 

 canal from Norriston to Philadelphia. Some lime stone 

 of uncommon appearance, at or near DilVs or Eickel- 

 herger's tavern, on the great road from York to Carlisle, 



