460 



POPULAR SCIENCE MONTHLY 



A^. #1^ 



cality in the section under consideration formed the subject of a 

 separate lesson, in \vhicli its structural features and the more im- 

 portant events of its history were presented. Special attention 

 was given to tracing the relations of the existing surface features 

 of each district to its geological structure, thus connecting the 

 ]>hysical geography and geology of the region. These lectures 

 were based on a large amount of original investigation and 

 results reached by Professor Crosby in his studies of the Boston 

 basin." 



During the winter of lS86-'87 Prof. AV. M. Davis delivered a 

 course on Problems in Physical (ieographic Classification, treated 

 of in tAVO lessons, and the Laws of the Evolution of the Principal 

 Topographical Types occupied the remainder of the course. Pro- 

 fessor Davis gave the class 

 the benefit of the results of 

 his investigations, which were 

 original contributions of im- 

 portance to the progress of 

 physical geography. " The 

 graphic manner of illustrat- 

 ing the lessons upon the Gla- 

 cial period and the effects of 

 the great glacier upon the 

 area of the Great Lakes was 

 very effective. This was 

 sliowu by means of a relief 

 model whose surface was 

 composed of an ingenious ar- 

 nmgement of overlying and 

 <lirt'erently painted surfaces. 

 Ry removing these in succes- 

 sion the lecturer traced the 

 w ,,.,,.. M 11. Nn.Ks. \\\\o\e history of changes fol- 



lowing u])on the recession of 

 a continental ghicier and its effects upon the surface waters. . . . 

 These lessons were so novel and useful to teachers that he was in- 

 vited tr» give a course of ten lesions during the next winter upon 

 the physical geography of the United States. New matter, 

 new models, and more extended illustrations were used in this 

 course. The objects of the course w('i-(>: To illustrate the value 

 of systematic classification in the study of pliysical geography in 

 order that forms of similar origin might be grouped together; to 

 advocate the ini|)ortance of studying the evolution of geographic 

 forms in time, so that forms siniihic in orioin but dissimilar in ace 



