Sierra Madre Project 5040

The mag file contains many shifts in the totmag and no attempt was 
made to adjust for them.  For the whole state of Wyoming map, the
mag was adjusted and the best grid possible for it is available 
from:
http://pubs.usgs.gov/of/2000/ofr-00-0198/

There are still artifacts and line shifts in the grid that 
could not be resolved.