INTRODUCTION 



all articles of outstanding importance are referred to in the text. All publi- 

 cations referred to are listed in the bibliographic index. For emphasis 

 on local areas of interest, die instructor can assign additional publica- 

 tions. 



The second type of exercise is the detailing of stratigraphic successions 

 in the different basins and mountain systems. This in itself would consti- 

 tute an extensive course in stratigraphy, but perhaps for local interest, 

 certain stratigraphic details can be fitted into the structural picture. 



The third type of exercise is the assembling from the book of all the 

 structural events that occurred nation-wide for each of the periods. Since 

 the book is organized chiefly on a geographic or provincial basis, it will 



be an excellent review to cut across provinces on a time basis and sum- 

 marize the events over the entire continent for each period. 'Ih< 

 paleogeologic and paleotec tonic maps and the- bri< i discussion that 

 companies them in Chapter 3 already do this, hut no part of the text is 

 devoted in detail to it. 



The fourth type of exercise is the tracing of the geologic history of a 

 county or a state. The commonest types of reports are those that de- 

 scribe the geology of an area with political boundaries, and it will ser\e 

 the student as a good lesson to write a history of such a region. He will 

 have to draw his information from several structural provinces and will 

 find his organization, if complete, both long and complex. 



