216 Letters of Mr. Brongniart with remarks. 



draulic works to any extent ; while the surrounding coun- 

 try is such as to admit of an agricultural settlement. 



I accompany this report with a geological chart of a ver- 

 tical section of the left bank of the Mississippi at St. Peters, 

 Embracing a formation of native copper, and in which the 

 superposition of the layers of rock, and the several subde- 

 posites forming the alluvial stratum, exhibit a remarkable 

 order. The curvatures in the lines of the alluvial stratum, 

 represent a natural mound or hillock recumbent upon the 

 brink of the river, which has partially fallen in, thus expo- 

 sing its internal structure. The formation was first noticed 

 by the garrison who quarried stone for quicklime, and for the 

 purpose of building chimneys, at this spot. The masses of 

 copper found are all small, none exceeding a pound in weight. 

 I have the honour to be sir, 

 with great respect, and regard, 

 your most obedient servant, 

 (Copy.) HENRY R. SCHOOLCRAFT." 



Art. II. — Miscellaneous observations relating to Geology, 

 Mineralogy and some connected topics, in extracts of let- 

 ters from Mr. Alex'r. Brongniart, member of the Roy- 

 al Academy of Sciences, Engineer of Mines, 8fC. of Paris 

 with remarks by the Editor to whom the letters were ad- 

 dressed. 



The observations of Mr. Brongniart, especially on some 

 American localities will probably be interesting and instruc- 

 tive to others in this country, as they have been to us ; this 

 has induced us to give publicity to remarks which although 

 not forwarded for this purpose, cannot fail to do honour to 

 their respectable author. 



His first letter, dated Oct. 9, 1819, is a reply to one ac- 

 companying American specimens transmitted to him, and 

 about some of which his opinion was asked. Mr. Brongni- 

 art observes : — 



"I transmit you to-day through the intervention of Mr 

 Doolittle, 



"1. A collection sufficiently complete, of substances 

 adapted to the manufacture of porcelain, and illustrative of 

 the principal changes and processes which these substance?; 



