160 



REFERENCES FOR THE DIAGRAMS. 



No. 



Plate. 



Page. 



1 



1 



17 



2 



1 



40 



3 



1 



41 



4 



1 



41 



5 



1 



42 



6 



1 



67 



7 



1 



67 



8 



2 



71 



9 



2 



87 



10 



2 



101 



11 



2 



101 



12 



2 



101 



13 



2 



104 



14 



3 



106 



15 





108 



16 





125 



17 





133 



18 Section from Georgetown, D. C. to Green Bay. 



19 Section from Green Bay to Prairie du Chien. 



20 Section from Prairie du Chien to Coteau de Prair 



