35 square km or ~33.3% of the former area of EL 1940, comprising a single block in the south, has recently been relinquished due to its now perceived diminished prospectivity for base metals and for diamonds. Seismic and gravity surveys were employed to assess the mineral potential, particularly for alluvial diamonds, of an area in the central Flinders Ranges' intramontane Willochra Basin, located 30 km north-east of Quorn. The northern part of this basin, which is crossed by the Wirreanda and Radford Creeks, is deemed prospective because at a higher level these creeks debouch from the Springfield Basin region, where diamonds are known to occur in Triassic conglomerates that may have a nearby primary source. In April 1991 and in May 1992, two small seismic reflection survey profiles totalling 10 line km were recorded on EL 1940 as academic research projects, with the assistance of Flinders University technical personnel and equipment, which identified reflective horizons within the Cenozoic sediment fill of the Willochra Basin. Limited responses were also seen from within the underlying westwards dipping Neoproterozoic bedrock, down to ~2 km depth. A 1 km wide trough was mapped, which may have faulted boundaries, that is thought to have formed in Cambrian or Permo-Triassic times. Late in 1994, gravity data were read from 115 stations spaced at 50 m intervals along three traverses for a total coverage of 10 line km, to profile part of a significant local gravity low recognised on existing regional data, that is located in the north-eastern corner of the Willochra Basin. It is concluded that several Cainozoic and Neoproterozoic reflectors, correlatable with nearby borehole stratigraphy, have outlined a 1 km - wide basin structure possibly equivalent to the Springfield Basin to the east. A gravity low over the seismic anomaly indicates a northeast - trending, possibly fault - bounded structure. The primary exploration target, estimated to be at >200 m depth, may be interpreted as 'cratered' kimberlite pipe sediments, a Triassic coal basin or a diapir. Shallow reflectors are attributed to channel gravels, the shallowest of which were intersected in shotholes. These gravels are also prospective for diamonds.