ACKNOWLEDGEMENTS 



The writer wishes to express her indebtedness to Dr. J. A. Bow- 

 nocker, State Geologist of Ohio, for a position on the Geological Survey 

 of Ohio while the necessary field work was being carried on, and for 

 the many helpful suggestions which he has given concerning the work; 

 also to Mr. Wilber Stout, of the Geological Survey of Ohio, not only 

 for his aid in collecting fossils and for the suggestion of localities where 

 collections could be obtained, but also for his help with the stratigraphy 

 of the Pottsville formation and for the kindly interest which he has 

 taken in every phase of the work. It is Jikewise a great pleasure to 

 the writer to acknowledge her obligation to Dr. George H. Girty of 

 the United States Geological Survey, for the valuable assistance which 

 he has given in the verification of new species and of obscure or doubt- 

 ful forms. Lastly, thanks are due to Mr. Raymond E. Lamborn, 

 Dr. Guy W. Conrey, and Mr. Clarence F. Moses for the collections 

 of fossils made by them, as given in the register of localities, to Miss 

 Charlotte Morningstar for her assistance in collecting fossils, to 

 Professor J. E. Hyde of Western Reserve University, for the use of his 

 collections of Pottsville fossils, and to Professor G. F. Lamb of Mount 

 Union College, for the suggestion of localities in Stark and Mahoning 

 counties where collections could be made. 



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