PREFACE. vii 



knowledgments that have been made in connection with the annual 

 reports and in other appropriate ways, tlie corps desire to tender this 

 general expression of their appreciation of the numerous courtesies 

 of which they have been the recipients. 



It is due also to those whose results do not appear in an individual- 

 ized form, to call attention to the analytical work of Prof. W. W. 

 Daniells, of the State University ; of Mr. Gustavus Bode, of Milwau- 

 kee; and of Mr. E. T. Sweet, recently of Madison; to the paleonto- 

 logical identifications of Prof. K. P. Whitfield, of New York, and to 

 the drafting of Prof. W. J. L. Nicodemus and Mr. A. D. Conover, of 

 the State University. 



An expression of indebtedness is also due Prof. R. P. Whitfield, 

 Hon. Geo. H. Paul, Prof. A. Salisbury, G. D. Swezey, J. II. Cham- 

 berlin and C. S. Bacon, for reading portions of the proof on subjects 

 with which they are especially familiar. 



The provision which has been made by the commissioijers of pub- 

 lic printing for the publication of the work has proved wise and 

 judicious, as well as highly economical. 



The mechanical execution of the work is the best witness that can 

 be offered as to the skill and faithfulness with which the printers and 

 lithographers have performed their respective tasks. The execution 

 of large geological maps is confessedly a work of much difficulty, and 

 great credit is dae the lithographers for the obliging and liberal man- 

 ner in which they have performed their work. In several instances 

 they have exceeded the requirements of their contract. 



