X PREFACE. 



but the greater part for the third volume, as well as extensive collections 

 in the higher rocks of the New-York series for the succeeding volumes. 

 Besides these, I had made large collections of fossils in the same series 

 of strata in the west, for the purpose of comparison with the New-York 

 species. In this way, as well as in examinations of the rock formations 

 in situ over a large part of the Western States for the purpose of de- 

 termining the parallelism of the formations, I had already made great 

 pecuniary sacrifices in carrying on the work. Under these circumstances, 

 therefore, and with the new aspect presented by the law of 1850, and 

 the action of the Commission relative thereto, I could no longer devote 

 myself to its prosecution, and consequently made other arrangements 

 for the occupation of my time, which, however, left me still some op- 

 portunity to continue my investigations in this work. As the contracts 

 between the State and the engravers continued in force, the engraving, 

 after 1851, was carried on somewhat slowly ; my frequent and protracted 

 absence rendering it impossible for me to give that personal attention 

 to it which a work of this kind so fully demands. In order to prevent its 

 entire cessation, I employed a person as an assistant (who afterwards 

 became my draughtsman) ; the lithographer volunteering to contribute 

 to pay a portion of the expense of such assistant, that his own work 

 might not cease entirely. In this way the work was continued till 1855 ; 

 no compensation whatever being paid to the author during this period. 



In the latter part of 1854 and beginning of 1855, the attention of 

 the then Secretary of State, Hon. E. W. Leavenworth, was called to the 

 consideration of this subject by Professor Dewey of Rochester, who had 

 taken some pains to procure information in relation to the state and 

 progress of the work. Mr. Leavenworth, with his enlightened views and 

 the patriotic desire to see a work, which had been begun by a wealthy 

 and powerful State, completed in a proper manner, inquired into its 

 actual condition, and, finally, when I had decided to abandon it al- 

 together, procured the passage of a law, giving to himself and the 

 Secretary of the Regents of the University the power to make such 

 contracts and provide such means as were necessary for carrying it on 



