FIGURE 1. Smithsonian Grid Track, April 1966* 
* 
+ 
4 + 4- 
1 Inch = 1 = 60 Miles 
I — Entry and Departure Points 
Diurnal Travel 
Nocturnal Travel 
169* 
±/ 7 ' 
+16 # 
+ IS 
+/f 
~\~I3 * 
+ /2* 
