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The magnetic properties of a massive hematitic body have been determined. Measurements were made of direction and intensity of remanent magnetism with an astatic magnetometer. One group of specimens has a northeast direction and a second group has a southwest direction. Of these two groups the southwest direction is considered the normally magnetized position. Average values are calculated for the two groups and then combined to give the total remanent magnetism. The induced magnetism was determined and added to the remanent to give gross magnetic effects.

The remanent magnetism of a suite of serpentine specimens from the western part of the Sierra Nevada has an average declination of 32° and a dip angle of 84°. The average intensity is 80×10−5 emu/cm3. The induced magnetism has an intensity of 218×10−5 emu/cm3 and a declination of 17° at +62° as calculated from susceptibility data and from the intensity and direction of the earth's magnetic field. The resultant of remanent and induced magnetism is the total magnetism, which has a declination of 17° at +66° and an average intensity of 320×10−5 emu/cm3. A curve for total magnetism as determined from individual specimens is found to correlate with a measured ground magnetometer profile of the area, which has a maximum anomaly of 6000 γ. Comparison of the magnitudes of remanent, induced, and total magnetism suggests that the total magnetism is primarily a function of induced magnetism. The maximum anomaly is, however, related to large components of both remanent and induced magnetism. Comparison of magnetic properties with chemical analyses of the rocks suggests a lack of correlation between the two. It appears that the variance in magnetic intensity is generally related to the grain size of the magnetite.

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