ROLLIN D. SALISBURY 
103 
when reached from the northeast proved ten times more effective 
when approached from the southwest. Some of the gravels of the 
Mississippi Embayment were regarded as pre-Pleistocene in age 
and with them were correlated the gravels of the Driftless Area 
of Wisconsin, Iowa and Minnesota. 
Of his work on the United States Geological Survey, in differ¬ 
ent parts of the country, much might be said. He wrote the glacial 
sections of a number of the atlas folios of Wyoming, New Jersey, 
Pennsylvania and New York. 
The work in New Jersey prosecuted while Geologist in Charge 
of the Pleistocene Deposits on the New Jersey State Survey called 
forth many memoirs and several more pretentious monographs. 
Of the latter the one on the Physical Geography of New Jersey 
is a model for a state report on this subject; while the report on 
the Glacial Geology of New Jersey formed a bulky volume of 
800 pages illustrated by over sixty plates. The descriptions of the 
old drift and the fluvial deposits are especially noteworthy. Be¬ 
sides giving full discussion of the character, distribution and 
origin of the Glacial drift of the State, there are instructive chap¬ 
ters on the development of the eastern ice-sheet, and on the relief 
and drainage changes produced by it. This volume contains also 
what is his most complete account of the history and causes of 
Glacial climate. 
Serving for several years as member of the Commission on the 
Geological Survey of Illinois, to which he was appointed by Gov¬ 
ernor Frank O. Lowden, he was able to guide the investigations 
into most productive channels. It would be difficult to measure 
fully the great activities which he entered into in this connection. 
Professor Salisbury especially excelled in the preparation of 
geological text-books for students. His chief work in this direc¬ 
tion was, of course, in collaboration with Professor Chamberlin, 
in three volumes. This well-known work will long remain the 
standard American exposition of the subject of Geology. For 
college use an abridged edition in one volume was issued. An¬ 
other important text was the Physiography, in one bulky volume 
of 800 pages. Then there was a series of laboratory manuals by 
Salisbury and Trobridge, such as the Interpretation of Geologic 
Maps, Laboratory Exercises in Structural and Historical Geology, 
and Studies in Geology. A series of little monographs on physio- 
