PREFACE v 



those by Dana, Chamberlin and Salisbury, Pirsson and Schuchert, 

 LeConte, Scott, Norton, Blackwelder and Barrows, Geikie, Kayser, 

 and De Lapparent, have been freely consulted, and due acknowl- 

 edgment is here made for the help derived from these sources. 



Among those who have read portions or all of the manuscript 

 are the following: Dr. J. M. Clarke and Mr. C. A. Hartnagel 

 of the New York State Museum; Professors W. B. Clark and 

 C. K. Swartz and Mr. E. W. Berry of the Johns Hopkins Uni- 

 versity; and Dr. L. W. Stephenson of the United States Geological 

 Survey. Special acknowledgment is made to these men for valu- 

 able suggestions and criticisms, but the author holds himself 

 strictly responsible for all errors the book may contain. 



WILLIAM J. MILLER 



Smith College, 



Northampton, Mass., 

 August, 1916 



