Sandstone shorelines can weather into strange forms. Examples in the Nanaimo area include the cave-like 'Malaspina galleries' and honeycomb weathering along the shores of the Gulf Islands. The cause of the strange shapes is related to variation in the mineral cement that holds sandstone together. Cemented sandstone is more resistant to erosion and forms ridges, 'lips', and cannonball-like 'concretions', whereas sandstone that is only partially cemented will erode more easily, resulting in depressions and caves.

honeycomb weathering and concretion

Malaspina Galleries