Routine measurements of remanent magnetization in 13 cores from Yellowstone and Jackson lakes in northwestern Wyoming have yielded a tentative curve of inclination for the past 3000 years. There is general agreement of magnetic inclination among several cores in both lakes, archeomagnetic data, and the directly observed modern sedimentation rate in Jackson Lake. However, declination plots are not correlatable. Remanent intensity systematically decreases with depth in most cores. Intensity and coercivity vary more from core to core than with depth. Water content is very high, up to 90% by volume even at the bottom of the cores. This circumstance may account for the high degree of scatter in the remanent directions. Substantial systematic changes of remanence were observed after allowing samples to dry.