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/ J -O 
DEDICATION. 
To His Excellency 
DAVID B. HILL , 
Governor of the State of New York : 
Sir : 
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 Palaeontology 
of 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 Yol. V, part 1, and to be published as Yols. 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 
included. 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 
