PREFACE. XV 



use of some interesting specimens of recent collection and information concern- 

 ing certain horizons in the Lower Carboniferous strata, and also the abundant ma- 

 terial of his earlier collection ; from Prof E. W. Claypole, the use of specimens, 

 as well as information concerning the geological relations of certain species ; 

 from Pres. E. S. Brainerd and Prof. H. M. Seely, of Middlebury College, Vt., 

 the use of specimens from the Calciferous horizon, which have since been 

 donated to the State Museum ; from Prof. Geo. H. Perkins, of the University 

 of Vermont, the use of specimens ; from E. E. Teller, of Milwaukee, Wis., 

 and F. A. Sampson, of Sedalia, Mo., similar favors. Acknowledgments are 

 fui'ther due to Mr. F. A. Blair, of Sedalia, Mo., and Dr. J. H. Britts, 

 of Clinton, Mo., for the use of specimens and especially for a collection 

 of Choteau limestone fossils from the former; also to W. H. R. Lykens, 

 S. J. Hare, F. W. McIntosh, of Kansas City, for specimens of Coal Meas- 

 ure fossils ; also to Prof Thomas B. Stowell, of Cortland (now of Potsdam), 

 N. Y., W. L. Brownell and D. S. Chatfield, of Syracuse, and E. B. Knapp, of 

 Skaneateles. To Prof B. K. Emerson, of Amherst, Mass.; to Dr. C. E. 

 Beecher, of New Haven, Conn.; and to E. 0. Ulrich, of Newport, Ky., thanks 

 are due for specimens and information ; also to W. T. Knott, of Lebanon, and 

 Mr. E. C. Went, of Frankfort, Ky.; to Prof William Libbey, of Princeton, N. J., 

 through Moritz Fischer ; Prof Joseph Moore, of Earlham College, Richmond, 

 Ind. ; to Col. C. C. Grant, an old and valued correspondent, and Mr. William 

 Turnbull, of Hamilton, Ontario, and to Mr. B. E. Walker, of Toronto, for speci- 

 mens from the Niagara and Hudson River groups ; to Professors Oliver Marcy, 

 of Evanston, HI., Edward M. Shepard, of Springfield, Mo., W. H Barris, of 

 Davenport, la., and S. S. Gorby, State Geologist of Indiana; to L. A. Cox and 

 D. G. Anderson, of Keokuk, la., for brachiopods of the Keokuk group, presented 

 by them to the State Museum ; to R. R. Rowley, of Curryville, Mo.; to Miss 

 Mary E. Holmes, of Rockford, Victor E. Phillips, of Olney, and J. H. South- 

 well, of Rock Island, and to W. R. Head, H. H. Hindshaw, and Victor C. 

 Alderson, of Chicago, Illinois. 



Among foreign friends and correspondents, my first acknowledgments are due 

 to the late Thomas Davidson, of Brighton, England, for many years of personal 



