To Dr. J. S. Newberry, Stale Geologist : 



Dear Sir: I have the honor to respectfully sul^mit to j^ou the following report on 

 the Fossil Corals of the State of Ohio. In addition to the true Corals, I have in- 

 cluded in this report descriptions of some of the more abundant and characteristic 

 Polyzoa, as well as of a remarkable group of Silurian and Devonian Sponges, both of 

 which come under the head of " Corals," commonly so called. 



As the specimens of various of the species of Corals are in a condition of preserva- 

 tion which allows of nothing more than the mere determination of their occurrence 

 in given formations, I have not always thought it necessary to give descriptions of 

 these, especially when they are well known forms ; but I have, on the contrary', 

 thought it sufiicient to merely note their presence. 



Many of the specimens, on the other hand, are unique in their exquisite condition 

 of preservation. Some of the previously recorded forms exhibit characters not here- 

 tofore observed, and there is a large number, comparatively speaking, of species 

 altogether new to science. Of these I have in all cases given a full description, 

 accompanied, where practicable, by illustrative figures. 



I desire, in this connection, to acknowledge the deep obligation under which I am 

 to Mr. U. P. James, of Cincinnati, for the use of numerous rare and often unique 

 specimens from his large and valuable collection of fossils from the Cincinnati rocks, 

 as well as for the valuable information which he has afforded me on various points, 

 which I should otherwise have found it difficult to elucidate. I am also greatly in- 

 debted to Prof. Edward Orton, President of the Ohio Agricultural and Mechanical 

 College, for the liberality with which he placed at my disposal many interesting 

 specimens from his private collection, and for the cordial assifctance which I have re- 

 ceived from him in my inquiries. 



Finally, in justice to myself, I may state that I have had to contend with some ex- 

 ceptional difficulties in the preparation of this report. I have not, namely, been 

 always able to compare certain of the known species with typical examples of the 

 same from other regions, and have, therefore, been compelled to decide as to their 

 characters simply from the evidence actually in my possession. Secondly, I have 

 found it impossible to obtain in this place certain of the memoirs upon this class of 

 organisms, to which I would otherwise have gladly referred. In some instances, 

 therefore, I have been unable to arrive at decisive conclusions on points which could 

 otherwise have been decided without difficulty, and I have not always been in the 

 position to give the necessary references, or to complete the synonymy with absolute 

 fullness. 



I have the honor to remain, dear sir. 



Yours, very i-espectfuUy, 



H. Alleyne Nicholson. 



University" College, Toronto, May 11, 1874. 



