MAGNETIC METHODS 



229 



Fig. 112. — Magnetic traverse across a simple placer concentration in an old stream bed, in 

 Trinity County, California. (Jakosky, Arizona Mining Journal, Aug. 1931.) 



o Legend 



, — Bedrock Contour 



• Magneiomefer Siation _ 

 —"' IsodynamicConfour^Verfical Componerrf 



o Electrical Staiion 



Fig. 11.3. — Magnetic and geological contours on a gold placer property in Pinal County, 

 Arizona. (Magnetic contours dotted curves and geoelectrical bedrock contours solid curves.) 

 (Jakosky and Wilson, A.I.M.B. Geophysical Prospecting, Tech. Pub. 615.) 



