Vlll PREFACE. 



copied from the reports of Professor Hall. A few of the Paleozoic 

 figures, and many of those of later periods, are from original draw- 

 ings, made by Mr. F. B. Meek, to whose artistic skill and paleonto- 

 logical science the work throughout is greatly indebted. The draw- 

 ings were nearly all made on the wood, for engraving, by Mr. Meek ; 

 and the paleontological pages have had the benefit of his revision. 

 The name of the engraver, Lockwood Sanford, of New Haven, 

 also deserves mention in this place. 



The preceding paragraphs have been taken, with little change, from 

 the Preface to the first edition of this work, dated November 1st, 1862. 

 They remain true for this new edition. Yet the work has been for 

 the most part rewritten, and is greatly enlarged. The changes have 

 been made necessary, both by the progress in geological investigation 

 over the United States and British America, and by the general ad- 

 vance of geological science. 



During the interval since 1862, surveys have been going forward, 

 and have been partly or wholly completed, in California, the Terri- 

 tories over the summit and slopes of the Rocky Mountains, the States 

 of Minnesota, Iowa, Missouri, Louisiana, Tennessee, Illinois, Indiana, 

 Michigan, Ohio, North Carolina, and New Hampshire, and the Prov- 

 inces of Canada, New Brunswick, Nova Scotia, and Newfoundland. 

 These surveys have greatly extended our knowledge of American rocks 

 and mineral products, besides affording aid toward a deeper insight into 

 principles, and a clearer comprehension of the system that pervades 

 the earth's structure. Besides all this, large contributions to paleon- 

 tology have been made by some of the Reports, and most prominently 

 by the new volume of the New York series, by James Hall ; the 

 volumes of the Illinois Survey, by Meek, Worthen, Newberry, 

 and Lesquereux ; of the Ohio Survey, by Newberry and Meek ; 

 of the California Survey, under J. D. Whitney, by Meek and Gabb ; 

 of the Survey of the Territories, under F. V. Hayden, by Meek, 

 Cope, Leidy, and Lesquereux ; and of Canada, under Sir Wm. E. 

 Logan, by Billings, Dawson, and Hall. Various important me- 

 moirs also have appeared in the scientific journals and in the publica- 

 tions of scientific societies and academies, and some have been issued 

 as independent works. 



Since the year 1862, through Scudder, we have our first knowl- 

 edge of the Insect-life of the Devonian ; through Leidy, Cope, and 

 Marsh, we have seen the meagre list of American Cretaceous Rep- 

 tiles enlarged, until it exceeds that from all the world besides ; and 

 through the same geologists, not only has the Mammalian fauna of 

 the American Miocene received additions of many species, but the 



