The Johnny Creek occurrence is located near the headwaters of Johnny Creek at the centre of the Horseranch Range, 85 kilometres south of Watson Lake, Yukon.

The stratigraphy of the Horseranch Range is comprised entirely of the undivided Proterozoic Ingenika Group (Swannell and Tsaydiz formations) consisting of mica schists, limestone, hornfels, skarn, granite, pegmatite dikes and quartz veins. The structure of the range is a doubly plunging, fault-bounded anticline and it has been suggested that it could be a metamorphic core complex (Plint, 1987). The group has been regionally metamorphosed to amphibolite grade (date unknown) and was displaced several hundred kilometres northward along the Tintina-Rocky Mountain Trench fault system.

The stratigraphy over the range has variable orientations but in the vicinity of the showing has a dip of 30 to 50 degrees southwest. Pyrite, pyrrhotite and trace chalcopyrite are found along cleavage planes, disseminated and in quartz veins in the mica schists. Black tourmaline is common as stubby crystals in vein and dike selvages, within quartz segregations and associated with garnet in pegmatites. Coarse-grained, brown tourmaline occurs with quartz and calcite in skarns adjacent to pegmatites.

Scheelite is restricted to the skarns and recrystallized limestones. The crystals range in size from 1 millimetre to 1 centimetre with an average range of 1 to 3 millimetres. A rock chip sample assayed 0.15 per cent tungsten oxide (Assessment Report 9401). Skarn assemblage minerals comprise calcite, garnet, diopside and vesuvianite.

In 1980, Amax of Canada Limited conducted geological mapping on the Sis claims. Six of nine samples taken on the property yielded greater than 1000 parts per million tungsten; the representative sample 80-RYT-59 yielded 1500 parts per million tungsten. Other elements analyzed for and found to be anomalous are fluorine, with maximum values of 1000 parts per million fluorine in silt (80-RXL-91) and 2800 parts per million fluorine (80-RXT-94) in skarn, and silver, with maximum values of 1.8 parts per million silver (80-RXL-83) in silt and 2.2 parts per million silver (80-RXT-94) in skarn. One sample (80-RXT-93) of black dense hornfels assayed 104 parts per million copper (Assessment Report 9401).

In 1997, Esmerelda Exploration Intl. conducted a four-day mapping and prospecting program on the MRX claims. At sample location MRX25, a boulder train consisting of very coarse-grained and strongly zoned pegmatite yielded very pale blue-green beryl crystals measuring up to 10 by 5 centimetres. Twenty mafic and ultramafic rock samples and three stream sediment samples were collected and assayed; results were ubiquitously low. Other sample locations yielded beryl crystals locally up to 3 centimetres across but typically under 5 millimetres in width and 2 centimetres in length. In total, eight samples yielded beryl crystals that were visible in hand specimen (Assessment Report 25453).