966 



Subsurface Geologic Methods 



Practically all well locations are referred to township, range, and sec- 

 tion lines; and if these lines are not shown on the map, it is diflBcult to 

 determine the correct locations. On very small-scale maps, township lines 

 may be undesirable; but, since county lines are tied in to the "land net," 

 they may be shown. It should be borne in mind that geographic coordi- 

 nates are not lines surveyed and marked on the ground, but, rather, are 

 the framework of the map projection. The subsurface geologist is con- 



TOWNSHIPS 



U.S.A. 



CANADA 



U.S.A. 



--T-l 



^a^ 



>- SE Va 



._| — 



SECTIONS 



9- 



__; i___ 



/3 



CANADA 



14 



'^ J // 



5 I 6 



4 I 3 



[-- f--^- + — 4--- 



IS I /6 



Q- 



10 j 9 



7 I 8 



Figure 521. Plats showing subdivisions of United States and Canadian 

 townships and sections. 



cerned primarily with legal subdivisions of state and federal surveys; and 

 all points of control will be located on the map by means of these sur- 

 veyed lines. 



Figure 520 illustrates the basic principles of the township system of 

 land surveys. There are many deviations from these principles, but ordi- 

 narily only small areas are involved. In Canada all townships are num- 



