The Leech 3 showings are on a cliff on the south side of the Cross River where it is joined by Alcantara Creek. The Cross River forestry road passes within 50 metres of the cliff at about "mile 17.6".

Initial report of magnesite at that location is recorded on Geological Survey of Canada Open File Map 634. Mapping and sampling by the Ministry of Energy, Mines and Petroleum Resources and prospectors have failed to located magnesite mineralization. However the style of alteration (dolomitization) of the local carbonates is very similar to that near the Baymag mine (082JNW001). Host rocks are carbonates (limestone and dolomite) of the Middle Cambrian Eldon Formation. This is the next major carbonate package above the Middle Cambrian Cathedral Formation that hosts known magnesite showings and the Baymag magnesite mine. Further chemical analyses of rock samples are being done by the Ministry of Energy, Mines, and Petroleum Resources in 1990.