VI PREFACE. 



drawn the chief illustrations of continental development from its rec- 

 ords. Facts fr^m other continents, however, have been freely added, 

 because required- both to give completeness to the treatise, and to 

 exhibit the comprehensiveness of geological principles. The aim has 

 been to present for study the successive phases in the History of 

 the Earth ; that is, of its Continents, its Seas, its Climates, its Life, 

 and of all its various characteristics, and not a mere series of facts 

 about rocks and their dead fossils. 



The author has endeavored to bring the volume into as small a 

 compass as consistent with a proper exhibition of the science ; and, 

 if some find its pages too numerous, he feels confident that quite as 

 many would pcefer greater fullness. The details introduced have 

 seemed to be necessary, in order that the march of events should be 

 appreciated. At the same time, the work has been adapted to the 

 general reader and literary student, by the printing of the scientific 

 details in finer type. The convenience of a literary class has been 

 further provided for by adding to the Appendix a brief synopsis of 

 the part in coarser type, in which each head is made to present a 

 subject, or question, for special attention. And, as many may not be 

 familiar with the science of Zoology, a review of the classification of 

 animals, with numerous figures, has been inserted as an introduction 

 to the Historical part of the Manual. 



The illustrations of American Paleozoic life have been largely 

 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, 



