(1) Magnetization acquired after deposition is called “post-depositional detrital remanent magnetization” (PD-DRM). Natural remanent magnetization (NRM) of very fine-grained deposits is regarded as a kind of PD-DRM, since the loose unconsolidated upper part of fine-grained sediments-say several tens of centimeters-does not have the stable NRM, the direction of which usually does not change with depth. The thickness of this upper part generally coincides with the depth at which magnetic particles are fixed by friction due to compaction, and it should be noted, especially in case of stratigraphic correlation, that there is a time lag in the magnetic record in a sediment. This time lag can be obtained dividing thickness by depositional rate. Since the depth at which magnetic particles are fixed is a function of the internal friction due to compaction as well as the applied magnetic field, it is possible to use this depth as a convenient parameter to indicate the degree of compaction.<br>(2) There are two contrary speculations concerning the correlation between climatic changes and geomagnetic intensity-variations. One maintains that an increase of the magneic moment corresponds to the surface coldness of the Earth. The other view insists that a decrease of the geomagnetic field is a cause of an ice-age. Both vieupointo are derived from paleomagnetic studies of fine-grained sediments; the former from investigations of deep-sea cores, and the latter mainly from study of a 200m-long core taken from Lake Biwa.<br>Since the rate of sedimentation is usually a few hundred to thousands of times greater in lakes than in the ocean, there must be some difference in time scale in these presumptive arguments. Moreover, there is another important difference in the nature of their arguments. The former concept regards the intensity of magnetization of sediments as a linear function of that of the past geomagnetic field, but the latter does not. To normalized the intensity variation of magnetization due to the difference in the quantity of the magnetic substances in the sediments, the latter concept requires as an indicator of the intensity of the past geomagnetic field, that the value be obtained through dividing the intensity of magnetization by that of saturation remanent magnetization.<br>It is pointed out that these differences in the two viewpoints lead to contrary conclusions.