60 square miles covered between Motpena (8 miles WSW of Parachilna) and Lake Torrens. No pre-Quaternary outcrops. Quaternary: yellow brown dune sand and clay, travertine up to 40 thick near margins of Lake Torrens. Nilpena area (see also envelope 130). No photo coverage. Grey limestone underlain by sandstones and quartzites (including Mount Michael trig. station), underlain by grey argillaceous limestone and calcareous shale, with purple slates near the top of the group. Flat topped hills capped with 10 of conglomerate with well rounded pebbles in calcareous cement occur west of Nilpena H.S. The conglomerate is underlain by travertine and gypsum, and is assumed to be of Pleistocene age.