Geophysical investigations, maps GP (series). 18. Total intensity aeromagnetic map of parts of San Miguel and Guadalupe Counties, N. Mex. (R.16E.-R.21E. and T.6N.-T.10N.), aeromagnetic survey 1946 by W. J. Dempsey and M. E. Hill. Scale 1 m.=1 in., contour interval 10 gammas. Washington, D. C, 1950.