Vlll PREFACE. 



The Manual has been adapted to two classes of students, — - 

 the literary and scientific, — by printing the details in finer 

 type. The convenience of a literary class has been further pro- 

 vided for by the addition of a brief synopsis of the work, in 

 which each head is made to present a subject, or question, for 

 special attention. 



In the preparation of the American part of the volume, the 

 author has freely used the reports of the various geological 

 surveys of the country, the memoirs published in the different 

 scientific journals and transactions, and other works bearing on 

 the subject. He has also drawn from his own Memoirs and Ex- 

 ploring Expedition Reports, especially on the subjects of Coral 

 islands, — Volcanic islands, — the Formation of Valleys by the 

 action of rivers, — the General Features of the Globe, and their 

 origin, — American Geological history, — and the Temperature 

 of the Globe, as exhibited on the Physiographic Chart. 



The illustrations of American Palaeozoic life have been 

 largely copied from the Reports of Professor Hall. A few of 

 the Palaeozoic figures, and many of later periods, are from 

 original drawings made by Mr. F. B. Meek, to whose artistic 

 skill and palaeontological science the work is, throughout, greatly 

 indebted. The drawings were nearly all made on the wood for 

 engraving by Mr. Meek; and the palaeontological pages have had 

 the benefit of his revision. The name of the engraver, Lock- 

 wood Sanford, of New Haven, also deserves mention in this 

 place. 



In selecting figures of foreign fossils for the Manual, those 

 used in Lyell's and other standard English works have, w T ith 

 few exceptions, been avoided, so that the student owning any 

 of those volumes will have additional illustrations of the 

 science. Many of the foreign figures are from the beautifully 

 illustrated " Paleontologie et Geologie" of Alcide d'Orbigny. 



The author would make acknowledgments to his countrymen 

 for the readiness with which they have furnished aid, whenever 

 appealed to, and especially, for oft-repeated favors, to J. P. 

 Lesley, of Philadelphia; J. S. New t berry, of Cleveland, Ohio; 

 Arnold Guyot, of Princeton, N.J.; L. Lesquereux, of Co- 

 lumbus, Ohio; E. Billings, of Montreal, Canada; E. Jewett, 



