xii ICE RECESSION IN NEW ENGLAND 



comprises investigations in the Connecticut Valley from Hart- 

 ford, Conn., to St. Johnsbury, Vt., and in the Merrimac Valley 

 around Concord, N. H. Field work lasting two months was 

 carried on during the same season in the Hudson and Champlain 

 Valleys and north of St. Johnsbury, but little use is made here 

 of the material collected outside New England. While a chro- 

 nology of the ice retreat from Hartford to St. Johnsbury has 

 been obtained, this is not connected with present time; and so 

 the question, How long ago? cannot be answered. 



No time and trouble have been spared to make the normal 

 curve, which has been compiled from the original measurements, 

 as accurate as possible with respect to both number and thickness 

 of the varves so that it may form a reliable framework for future 

 detailed studies. It is in the extraordinary possibilities of the 

 geochronological studies for accuracy and for detail, as well as 

 in their wide bearing not only on geology but also on other 

 fields of science, particularly geography, climatology, and 

 archeology, that their scientific value and great importance are 

 to be found. 



The field work was carried out on a scholarship from the 

 Sverige Amerika Stiftelsen in Stockholm and a special grant 

 from the National Research Council in Washington, and with 

 private means. 



The successful completion of this field work and the working 

 up of this memoir are principally due to the kind interest of 

 Professor J. W. Goldthwait of Dartmouth College; Professor 

 Edward B. Mathews of Johns Hopkins University; Mr. Robert 

 W. Sayles, curator of the Geological Museum of Harvard 

 University; and the American Geographical Society of New 

 York. Professor Goldthwait has ever since our first meeting 

 aided me in word and deed. He has participated in the field 

 work, and he has compiled the map (PI. VI), which has made it 

 possible to correlate the history of New England with that of 

 the Great Lakes. During the writing of the memoir, at Dart- 

 mouth, his advice and help have been of the greatest value. 

 He has also bestowed much labor on its form. Professor Mathews. 



