4 
CAVE AND CLIFF DWELLERS. 
will take the pains to look at a map of 
this portion of Mexico he will see that it 
projects into the United States some dis¬ 
tance beyond the average northern bound¬ 
ary, the Rio Grande being to our east, 
and an “ offset,” as we would say in sur¬ 
veying, being to our west, this “ offset ” 
running north and south. This flat pen¬ 
insula projecting into our own country 
can be better understood by visiting it 
and comparing it with the surrounding 
land of the United States, coupled with a 
history of the country. Roughly speak¬ 
ing, the Mexican-United States boundary, 
as settled by the Mexican War, followed 
the line of the Southern Pacific Railway 
as now constructed, and the so-called 
Gadsden purchase from Mexico of a few 
years later fixed the boundary as we now 
see it, giving us a narrow, sabulous strip 
