In response to the recognition of unusual mafic and ultramafic rock types in the Mulgathing area by Kennecott Explorations during their tenure of SMLs 261, 333 and 491 between 1968 and 1971, diamond explorer Otter Exploration has carried out further geochemical and petrographic studies to more fully assess the mineralogy of these intrusive rocks, in view of their possible kimberlitic and carbonatitic associations. The assays returned are interpreted as showing anomalous alkali metal and also slightly anomalous yttrium contents in these rocks, which are regarded as occurring in a comparable geological setting to kimberlite / carbonatite bearing terrains in other parts of the world. A programme of trenching and bulk sampling of the intrusions where they outcrop, and of soil sampling where they underlie cover as indicated by magnetic data, is recommended to allow examination for kimberlite indicator minerals.