The investigations on clays progressing at the Macaulay Institute arefundamentally connected with pedological studies. The general aim of theseinvestigations is to provide evidence which we believe will give us a betterinsight into the fundamental differences between the soil types as mapped inthe field and provide us with an explanation of certain of theircharacteristics and properties. Within the last year a systematicinvestigation has been commenced into the clay minerals associated with eachdifferent soil type in Aberdeenshire. The methods being used are X-rayexamination and differential thermal analysis. A brief account of the X-raywork has been given by Mr G. F. Walker.