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The feasibility is discussed of using anisotropy of magnetic susceptibility to find preferred directions of grain orientation and current directions in sediments, and it is concluded that it should be possible to find these directions in silts and sands containing between 0.01 and 1 % of magnetite.Some examples are given of the use of the method under controlled conditions, and it is shown to give the same result as optical grain orientation determination in one example and to predict the same current direction as macroscopic indications in two others. Some of the limitations of the method are suggested by examples in which the results would have been misleading if accepted unconditionally.

This work is a study of the magnetic properties of fine silts deposited in the laboratory. The results are described of a number of experiments in which a naturally occurring sediment was redeposited in an open flume under a range of controlled conditions. Measurements have been made of the directions of remanent magnetism of the redeposited sediments and of their principal axes of magnetic susceptibility.It is found that the deviations of the remanence direction and of the direction of maximum susceptibility caused by the movement of water over the bed during deposition can be accounted for by an extension of the theory in which the sediment is considered as an assemblage of quasi-spherical particles which roll on deposition into hollows in the bed.In the interpretation put forward it is postulated that the effect of a water current is to rotate the particles through an angle p immediately before they touch bottom, the magnitude of p being determined by an equilibrium between the shearing couple and the magnetic restoring couple.A method has been found of correcting for the effects of currents in natural sediments from measurements of their remanence and anisotropy of susceptibility, and a field test of this method is suggested.

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