7(3 PROCEEDINGS OF THE AMHERST MEETING 



their enumeration. Robertson Brothers of Washington, Ward's Natural 

 Science Establishment of Rochester, The Lorenz Model Company of 

 Madison, and Krantz of Bonn are the principal dealers. 



SUGGESTED RELIEF MAPS 



The answers to the questionnaire indicate, however, that a number of 

 relief maps are* desired. Of these only a few will be indicated : 



1. It might be well to construct three relief maps, each about one foot 

 square, to show sink-holes, pot-holes, and kettle-holes. 



2. A set of three relief maps to show how a mountain range may be 

 cut back by "cirque action." An ideal landscape, based on Cloud Peak 

 and Phillipsburg, Montana, topographic sheets, might be used. 



3. Another set of relief maps might be made to show stream capture 

 of the normal type, stream piracy by subterranean drainage, and capture 

 by planation. 



4. One letter urges the construction of paleogeographic relief maps. 

 Prof. W. M. Davis gives the following warning : 



"A really educational series can not be limited to actual areas. . . . All 

 good teaching that I kuow of takes artificial examples or artificially limited 

 and selected and simplified examples to begin with. . . . Furthermore, the 

 models should be in series to illustrate relationships. Finally, they should be 

 associated with models of actual places ; but of the two, the ideal are much 

 more instructive." 



BLOCK DIAGRAMS 



In this connection reference should be made to the value of block dia- 

 grams. Although models give a better mental picture of topography and 

 geological structure than anything else except nature itself, and in some 

 models even better than nature, block diagrams are invaluable. Nothing- 

 has made the study of geology and physiography more real than the re- 

 markable block diagrams of Prof. W. M. Davis and those of his students 

 and followers. The advantage of diagrams of this kind lies in the fact 

 that they can be taken to his room by a student and studied at any time. 



Lantern Slides 



All the correspondents but one appear to believe firmly in the use of 

 lantern slides in teaching geology and physiography, but no entirely sat- 

 isfactory plan for enabling teachers to know what slides are in existence 

 and how they can be obtained has been suggested. 



The most practical suggestion is that tin's matter should be left in the 

 hands of some permanent organization. 



