VI PREFACE. 



ed a supplement to my fourth memoir, as well as some 

 observations on Lamarck's species of the Naiades, (to be 

 published in the Transactions of the American Philosophi- 

 cal Society) I found myself sufficiently at leisure to take 

 up the fossils from Claiborne, Alabama, which had been 

 so long in my possession, and which had not before been 

 described. The want of time alone had prevented an 

 earlier attention to them. 



