Quaternary alluvium comprising glacial boulder clays occur along the shoreline in the northern part of Crescent Bay near the northern tip of Texada Island. The clay contains few scattered pebbles. Bedrock is comprised of limestone and pillow basalt of the Upper Triassic Quatsino and Karmutsen formations respectively, of the Vancouver Group.

Testing revealed the clay is very gritty, slightly calcareous, but has fairly good plasticity when tempered with water. The air shrinkage is high at 8 per cent. On burning to Cone 010 (the temperature that most common bricks are burned at), the clay has a good hard body of light red colour. The fire shrinkage is zero and the absorption 16 per cent. When burned to Cone 6, the clay develops a good red colour and steel hard body, but the absorption is high at 15 per cent. At Cone 3 the body is dark red and almost vitrified. The shrinkage at this temperature is 4 per cent. This is a good common brick clay, but is not suitable for the manufacture of vitrified wares, as the shrinkage is too great and the softening point too low (Geological Survey of Canada Memoir 58, pages 99,100).