DEDICATION 



To His Excellency 



DAVID B. HILL, 



Governor of the State of New York : 



From the conimencement of the publication of tiie Natural History of New- 

 York, the successive volumes have been dedicated to the Governor of the State. 

 In accordance with this custom I have the honor to present to your Excellency 

 a new volume of the work, being the second one published under the provisions 

 of an act of the Legislature of 1883, being a continuation of the work on the 



PALiEONTOLOGY OF THE StATE OF NeW YoRK. 



This volume, together with one published last year, is devoted to the descrip- 

 tions and illustrations of the fossil bivalve shells known as Lamellibranchiata, 

 and completes the work upon that class of organisms. The two volumes em- 

 brace the descriptions of all the fossils of this class at present known to occur 

 in the higher geological formations of the State, viz. : The Upper Helderberg, 

 Hamilton, Portage and Chemung groups, with a small number from the 

 Waverly group, which has its chief extension beyond the limits of New York. 

 The material has been chiefly collected in the field, or acquired from collections 

 previously made during a period of more than forty years. The number 

 described in the entire work, from the formations above indicated, amount to 

 about 500 species which are arranged under 65 genera, and are illustrated upon 

 ninety-six lithographed plates, of which fifty-one are included in the present 

 volume. The number and variety of forms is believed to be greater than are 

 yet known from the geological formations of the same age in any other part of 



