The Shoshong-Makhware area, which covers approximately 1200 square miles west of the Mahalapye-Palapye rail track in Latitude 23°s, and longitude 26.5°w, contains several tholeiitic intrusions. These are probably differentiates of subterraneous magma body, which was roughly contemporary with the Bushveld Igneous Complex in the Union. The present author first visited the area in July 1957 and subsequently spent four months remapping and collecting the necessary material for a more detailed laboratory study. Mapping was done with the aid of aerial photographs, and where those were not available, resort was made to triangulation survey methods, using a prismatic compass. Inclinations of joints, faults and bedding planed were determined with the aid of a Brunton Compass. The laboratory work was carried out in both Department of Geology in the University of St Andrews, and also at the University of Cape Town. Particular attention was paid to the petrology, mineralogy and chemistry of the intrusive. A description of the techniques applied is given.