The Zone 4 skarn showing is located between Brandywine and Callaghan creeks adjacent to Highway 99 near the township of Whistler. The area is underlain by diorite of the Jurassic to Tertiary Coast Plutonic Complex and metavolcanics and metasediments of the Lower Cretaceous Gambier Group, preserved in the Callaghan Creek roof pendant. Pliocene to Recent Garibaldi Group volcanic rocks overlie the older rocks to the east.

Mineralization consists of sphalerite, chalcopyrite, pyrrhotite, pyrite, galena, covellite, argentite and electrum, contained entirely within a marble pod. Sulphides are intimately associated with calcsilicate minerals, primarily garnet and epidote, with both sulphides and calc-silicate minerals occurring in sporadic patches within the marble.

A 1.5-metre intersection from 1978 drill hole #1 contained 8.2 per cent zinc, 7.88 grams per tonne silver and 0.04 per cent copper (Assessment Report 7032). A six-metre random chip sample across a trench blasted in 1977 assayed 18.7 per cent zinc (George Cross News Letter No.179, 1977).