LETTER FROM THE AUTHOR. 



MR. JOHN R. PROCTER, 



Director Kentucky Geological Survey : 



DEAR SIR: The work of describing the fossil shells, or Mollusca, from the 

 Falls of the Ohio, which you kindly assigned to me some years ago, has, 

 unfortunately, been delayed by severe illness of several years' duration. It 

 was only during the past winter that I regained sufficient strength to complete 

 it. This monograph contains about two hundred and twenty species, forty- 

 three of which are new, and originally described by me. The descriptions 

 and illustrations of the balance are scattered over many different State 

 Reports, Monographs and Periodicals, accessible to only a few persons in 

 Kentucky, and, for this reason, it was necessary either to copy those figures 

 and descriptions, or to reproduce them from our own material. All of our 

 illustrations are original, with the exception of three or four, which are 

 copied from Prof. Hall's 27th Regents' Report. The drawing and engraving 

 was done by Mr. Chas. Starck, of the Louisville Lithographing Co., who 

 deserves great credit for the pains taken and the skill shown in the execution 

 of this work. Of the original descriptions of known species, I copied some 

 entirely. Coming, as they were, from the skillful pen of Prof. Hall, it was 

 impossible to improve them. Others I have remodeled, and some set aside 

 and replaced by new ones. In many cases, the descriptions were made from 

 single, not well preserved, specimens, which rarely showed the true characters 

 of the shells in their original condition, and, therefore, led to errors in the 

 descriptions. The large and excellent material now found in about a dozen 

 collections here in the Falls Cities, while enabling me to correct those mistakes, 

 has also compelled me to change descriptions coming from far superior palae- 

 ontologists. The larger number of our fossil shells were, heretofore, described 

 and figured by Prof. James Hall, of Albany, New York, in his numerous 

 reports and pamphlets, most all of which he presented to me, with the kind 

 permission to make the broadest use of his illustrations and descriptions. For 

 such exceptional generosity I can thank him only by this public acknowledg- 

 ment. The material used in the preparation of this monograph belongs partly 

 to my own cabinet, and partly to the collections of the following gentlemen : 



