It is nearly a year now since we commenced the systematic investigation ofour local soil clays in the North-East of Scotland by the powder method ofX-ray analysis. In Aberdeenshire, one of the most wide-spread SoilAssociations is the Insch Association, and this is the one I wantparticularly to talk about to-day. An association consists of soils derivedfrom similar parent material, and the parent material of the InschAssociation is till derived from basic igneous rock—mainly hypersthenegabbro, but sometimes with olivine also present.