DEDICATION. 



To His Excellency 



DAVID B. HILL, 



Governor of the State of New York : 

 Sm: -^ 



I have the honor to present a new volume of the Natural History of the 

 State of New York, being a continuation of the work on the Paleontology 

 OP THE State of New York. 



This volume is the sixth of the entire series, and the third published under 

 the provisions of chapter 355 of the laws of 1883, which directed that this 

 work be completed in five volumes beyond those at that time published. It is 

 devoted to the description and illustration of the Corals and Bryozoa of the 

 Lower Helderberg group, and to the Bryozoa of the Upper Helderberg and 

 Hamilton groups, and comprises over three hundred pages of text, and sixty- 

 seven plates, being the full amount of text and plates which could be used, 

 while making a proportionate allowance for the other classes of fossils, already 

 published as Vol. V, part 1, and to be published as Vols. VII and VIII under 

 this title. 



The entire number of species described is about 371, which are included under 

 70 genera and sub-genera. Of this number 328 species are illustrated in the 

 volume. In addition to these about 100 species of the same class of fossils 

 have been critically studied and drawings made for their illustration, but from 

 the restriction limiting the extent of the present volume these could not be 

 includedoT This does not, by any means, exhaust the number of forms known 

 to occur in these rocks. 



The volume must be regarded as only a partial record of our present know- 

 ledge upon this class of organisms, but at the same time I believe it will be 



