Richmond-Roanoke 1974  Project 6004D

The publication gives no information as to how the magnetic data may have been
corrected.  The only source for the magnetic data was in the radiometric file and,
therefore, labelled resmag.  Because no known corrections were applied to the magnetic
data, we are assuming it is total field magnetics but allowed it to remain listed as
resmag in the radiometric file.  A magnetic file was created from the radiometric file.

The rad data can be found in each of the above quads.  Mag for only part of the Richmond
is shown for the 1977 survey.  This mag data fills in the quad. and is at 2 mile line spacing.