DEMONSTRATION MATERIAL IN GEOLOGY 83 



the Geophysical Laboratory, and the United States and Canadian Geo- 

 logical Surveys get together and determine what apparatus should be 

 made. After a definite list has been determined on, the first cost of con- 

 struction could be divided among all and duplicates sold directly at cost, 

 or by a dealer, if it is found that some firm can produce them cheaply 

 and well. 



2. It is recommended that the following ten geological models be con- 

 structed, preferably six inches wide and less tj^an two and a half feet 

 long : 



(1) A section of the Coastal Plain of Alabama or Texas, to 

 show sedimentation, cuestas, and peneplains. 



(2) A section of the Piedmont Belt, to show foldings, intru- 

 sions, and peneplains. 



(3) An east-west section of the Appalachians, to show folding, 

 faulting, and peneplains. 



(4) An east- west section of the Great Plains, beginning with 

 the upturned beds of the foothills of the Rockies. 



(5) East- west sections of the southern Rockies. 



(6) An east-west section of the northern Rockies. 



(7) An east-west section of the Great Basin. 



(8) An east-west section of the Sierra Nevada. 



(9) An east-west section of the Great Valley of California and 

 Pacific Coast ranges. 



(10) An east-west section across the Hudson Valley from New 

 York City to the Highlands of New Jersey. 



It is also hoped that Hudson's model of Valcour Island, some of the 

 Field Museum Geological models, some of the Canadian Survey relief 

 maps by Dowling, and that by Adams will be produced commercially. 



3. It is recommended that relief maps be constructed to show the evo- 

 lution of mountain scenery by glaciation ; to show stream capture by sub- 

 terranean drainage, by planation, and by headward cutting of streams; 

 and to illustrate other subjects. 



4. The advantage of moving pictures of animated block diagrams is so 

 evident and the possibilities are so far-reaching that attention is particu- 

 larly called to this new method of teaching geology and physiography. 

 Any one who has the ability to do so is urged to begin the work because 

 it is firmlv believed that such films will be more eaoerlv sought after than 

 almost any other material in teaching. 



5. Attention is also called to the desirability of an illustrated dictiuii 

 ary of geological terms with references to other good illustrations. 



