INTRODUCTION. 
xiii 
lications of each one, would occupy more space than the author has at his 
command in this introduction; and moreover, few of these writers have pub¬ 
lished species from the State of New York. 
The following authors have published descriptions of species of American 
Palaeozoic Lamellibranchiata: 
Billings. 
Castelnau. 
Clarke. 
Conrad. 
Cox. 
Dawson. 
Dyer. 
Emmons. 
Gabb. 
Geinitz. 
Hall. 
Hartt. 
Haughton. 
Hayden. 
Hinde. 
James. 
Lea. 
Marcou. 
Marcy. 
McChesney. 
Meek. 
Miller. 
Morton. 
Newberry. 
Nicholson. 
Owen. 
Pitt. 
Salford. 
Salter. 
Shumard. 
Stevens. 
Swallow. 
Ulrich. 
de Verneuil. 
Vanuxem. 
Walcott. 
White. 
Whitfield. 
Williams. 
Winchell. 
Worthen. 
During a long interval, after the close of Mr. Conrad’s labors, very little was 
done in New York beyond the accumulation and study of collections, and the 
determination of specific forms for the illustration of the New York Devonian 
Lamellibranchiata. 
In 1869, the writer published “ Preliminary Notice No. 2 of the Fossil 
Lamellibranchiate Shells of the Upper Helderberg, Hamilton, Portage and 
Chemung Groups,” etc., to the number of eighty pages, which were issued in 
December of that year, and one hundred copies in this form were distributed. 
In January following the printing was resumed, and sixteen additional pages 
were printed. The pamphlet thus augmented, together with a supplementary 
page, stating the fact that the descriptions of other species were then in type, 
