The wholly cored SADME DDH Myall Creek RC1 was sited at the eastern extremity of the exposed Gawler Range Volcanics, and was completed [as a vertical hole] at 551.34 m total depth [the limit of drilling rig capability] on 26/10/1978, without reaching the base of the volcanic sequence. The rocks intersected consist of welded ash flows (dacite to rhyolite) and 5 m of silicified tuffaceous sediments. Altered basaltic lavas 45 m thick in the upper part of the sequence are correlated with basic volcanic rocks encountered to the east in Pacminex holes. The volcanic rocks in the drill core have been intensely altered and haematised down to the bottom of the hole. They may have been subjected to low temperature hydrothermal alteration at a later period.