Dr. J. S. Newberry, State Geologist: 



Dear Sir: In accordance with your expressed desire tliat tlie descriptions of Ohio 

 fossils, scattered through various pubh'cations, and in many cases inaccessible to the 

 general student in science, should be brought together in a classified form, with illus- 

 trations of the same, the accompanying descriptions and figures are offered as a con- 

 tribution in that direction. This work is necessarily incomplete, both from want of 

 time and for the want of means of illustration for the entire series. Under these cir- 

 cumstances it was thought better to confine the work mainly to the fossils of the 

 Hudson River, Clinton, and Niagara groups inclusive, giving, with the described 

 species, such new forms from the Ohio localities as might come under observation 

 during the progress of the work. But with this restriction it has been found neces- 

 sary to leave out some entire groups which it would be very desirable to illustrate, 

 and which have not j'et been described or illustrated in any American publication. 

 These are especially the Bryozoa and Corals of the Cincinnati beds and their equiva- 

 lents in other parts of the State, among which are many characteristic species requir- 

 ing much time for study, with careful descriptions and illustrations, to make them 

 available for the use of the student in Pateontology. 



In the outset it was proposed to give the same revision to the higher groups that 

 has been partially given to the lower; the figures of the Crinoidea from the Waverly 

 group were made in pursuance of that plan, but it afterwards became apparent that 

 the time and means at our disposal were insufficient for the work, and in consequence 

 nearly every thing from the age of the Corniferous, Hamilton, Portage, and Chemung 

 groups have been omitted from the present communication. 



During the progress of the work interesting specimens have been received from Mr^ 

 U. P. James and Mr. S. T. Carley, of Cincinnati, from IMr. Jesse Vanduzer, of Waynes- 

 ville, and President Edward Orton, of Columbus, Ohio, to whom we are under especial 

 obligations. Several other gentlemen of Cincinnati, Dayton, and other places, have 

 kindly offered to contribute specimens, but the necessity of restricting the limits of 

 the w^ork has prevented us from accepting their assistance in this direction on the 

 present occasion. 



Verj' respectfully, your obedient servants, 



James Hall, 



R. P. AYhitfield. 



