4 LETTEE TO THE GOVERINTOE. 



University, now of Genesee College, New York, is an important, nay an indis- 

 pensable addition to this report. Prof Emery lias performed his duties with a 

 zeal and conscientiousness worthy of all admiration and I bespeak for his work 

 the full confidence of the public. 



It is matter of the greatest satisfaction to myself that both of these gentlemen, 

 amid all the perplexities inseparable from our arduous and peculiar labors, have 

 placed me under especial obligations for their constant kindness. 



Besides the assistance of the gentlemen, regularly appointed to the work, I 

 have received important aid from others, much of which was rendered gratuit- 

 ously. The names of each of these persons will be found in the text in con- 

 nection with the matter furnished. Among the most important of this gratuitous 

 aid is a series of lists of elevations along the lines of nearly all the railroads in the 

 State, both finished and projected, furnished by their respective Chief Engineers ; 

 and the chapter on Meteorology and Climatology by Prof. T. S. Parvin. Prof. 

 Parvin's observations comprise the earliest and most extensive observations of 

 the kind ever made in the State. When it is remembered how intimately Meteor- 

 ology and Climatology are connected with the most important interest of our 

 Commonwealth, namely : Agriculture ; and how great an influence the presence 

 of forests has upon the climate of a region, in connection with the fact that the 

 woodland area of Iowa has constantly increased with the advancing settlement of 

 the State, the value of Prof. Parvin's observations for present and future consul- 

 tation will be quite apparent. 



I employed Mr. W. R. Morley to reduce the data furnished by the railroad 

 engineers, for use in the chapter on Physical Geography. In consequence of the 

 liberal kindness of those gentlemen, the only cost to the survey of that important 

 addition to the report has been the office-work necessary to prepare the material 

 for the printer. The list of elevations will all be found in the form of an appendix 

 (Appendix A) to this report. 



Learning that Mr. J. A. Allen, Ornithologist of the Museum of Comparative 

 Zoology, Cambridge, Mass., intended to spend the season of 1867 in Iowa to study 

 its birds, I invited him to make the camp of the Geological Survey his head- 

 quarters. He did so, and has generously furnished a list of the birds of Iowa 

 herewith accompanying this report as appendix B. The acknowledged im- 

 portance of ornithology in relation to our great interest — Agriculture — makes any 

 explanation of -the association of such a list with this report unnecessary. 



In consequence . ; of 2 the constant necessity of referring to the linear surveys of 

 the general government, in describing the geology of the State in this report, it 

 has seemed; necessary that a full explanation of the system upon which those 

 surveys are based should accompany it. I have therefore procured such an ex- 

 planation from Mr. Chas. W. Irish, Civil Engineer, who is well acquainted with 

 the subject in all its details. It accompanies this report as appendix C. 



The chemical department of the survey has been placed under important obli- 

 gations to Rev. Father Emonds, of St. Mary's Church, Iowa City, for the loan of 

 apparatus from his private laboratory, which it was impossible to obtain else- 

 where at the time it was needed. 



