iv PBEFACE. 



name included within brackets. The name of the Group of rocks is 

 generally abbreviated. Where the author, in the first instance, referred 

 his species to the wrong genus, such generic and specific name is 

 included within parenthesis immediately following the date of the publi- 

 cation. For instance, Delthyris is a synonym for Spirifera, and many 

 species have been erroneously referred to it; such are written in this 



manner: t, x, 



Spirifera arenosa, Conrad, 1838, (Delthyns arenosa), Ann. Kep. JN. 



Y., Oriskany sandstone. [Sig. sandy.] 

 Specific names never begin with capital letters. 



The author has endeavored to quote from the original publications, 

 and for kindness and assistance in obtaining access to them, he expresses 

 his obligations to Prof. James Hall, of Albany, New York ; Mr. C. D. 

 Walcott, of Trenton Falls, New York ; Prof. Leo. Lesquereux, of Columbus, 

 Ohio, and to Mr. Thomas Vickers, the able and efficient librarian of the 

 public library in the city of Cincinnati. A few of the works cited, how- 

 ever, were not within reach, and the references to these are therefore 

 second hand. In the attempt to make the catalogue of names complete, 

 within the scope of the work, the author visited several libraries and 

 otherwise used reasonable efforts for that purpose, but he has no doubt 

 that a few names have been omitted. The number of names in the book 

 is as follows : 



Generic names in Roman letters, 1,000 



Generic names in Italic letters, - - 200 



Specific names in Koman letters, 8,000 



Specific names in Italic letters, - - - 2,000 



Total number of g6nera and species, including 



synonyms, etc., - - - 11,200 



Some of the authors of generic and specific names have not been 

 familiar with the Latin and Greek languages, others have been careless 

 in the exercise of their knowledge when forming the new words, and 

 many names have been misprinted for want of careful proof-reading. 

 For these and probably other reasons, the specific names under a single 

 genus have been found with masculine, feminine, and neuter termina- 

 tions; no uniformity has existed in the terminations added to proper 

 names, and words have been otherwise incorrectly formed. So univer- 

 sally have these errors prevailed, that the author found in some Classes, 

 twenty-five per cent, of the names defective. In a conversation with 

 Prof. E. W. Claypole, of Antioch College, Yellow Springs, Ohio, (a gentle- 

 man thoroughly learned in the Latin and Greek languages) shortly before 

 commencing the publication, with regard to the etymology of words, and 

 the importance of following the laws of language in making the genders 

 of the adjective specific names correspond with those of the generic 

 terms, he very kindly profi"ered his assistance, for the purpose of making 

 all proper corrections in this regard. Publication was commenced in 

 February, and the proofs were sent to Prof. Claypole as rapidly as the 



