A bed of Lower Permian aged limestone trends northwesterly across the top of Mt. Layton for 2300 metres, 13 kilometres southeast of Terrace. The deposit outcrops over widths of up to 1000 metres. Bedding strikes 008 degrees and dips 35 degrees east. The limestone conformably rests on a sequence of greenstone, tuff, breccia, shale and argillaceous limestone.

The deposit is comprised of massive beds of white limestone 3 to 9 metres thick that contain a few fine, discontinuous blue bands. The beds are sometimes separated by 1.5 to 1.8 metres of sandstone.