A total of 35 cabletool foundation investigation holes were drilled along the centre line of the proposed North-East Transit Corridor route from McKinnon Parade to Tea-Tree Shopping Plaza, Modbury. The cabletool holes penetrated siltstone bedrock beneath clay, silt, sand and gravel beds that are 5 to 20 m thick. In places the bedrock was completely weathered down to a depth of 2-5 m below the soil horizon. Standard penetration tests were carried out at 1.5 m intervals in every drillhole to assess the bearing strength of the soil materials. Holes drilled adjacent to the River Torrens showed a static groundwater level approximately the same as the river level. Holes drilled along the Corridor route between the River Torrens and the Modbury Shopping Centre were dry, except for two holes (GS 3S; GS 3N) drilled at the Lyons Road grade separation; here the static groundwater level was intersected 4.0 m below the ground surface.