Palaeomagnetic studies of the Kapiti phonolite of Kenya

Specimens of Kapiti phonolite from sixteen sites were treated in an alternating field up to 900 Oe peak. Four sites were discarded on the basis of Watson's Criterion for randomness. Variations in various magnetic parameters along a vertical section of the rock indicate that a hard secondary component of magnetization of high coercive force is present in the surface samples of the rock — a possible cause for the poor grouping of directions of the remaining sites. Weathering may have introduced this component in the surface samples.