The Upper Brydon showing area is underlain by Pennsylvanian intermediate metavolcanic and metasedimentary rocks of the Stikine Assemblage, intruded by a small stock of the Late Triassic to Early Jurassic Copper Mountain Plutonic Suite, consisting of syenite to monzonite on the north and ultramafic rock on the south. This Stikine sequence is also intruded by Late Early Jurassic granodioritic intrusions of the Cone Mountain Plutonic Suite within a few kilometres of the showing and granite intrusions of the Paleocene to Eocene Sloko-Hyder Plutonic Suite within several kilometres.

In 1989 Shellex Gold Corp spent 2 man-days prospecting, sampling and mapping the RB 23 and 27 claims of the Phacops property. A total of 9 outcrop rock samples were collected at the northeast corner of RB 23 near the eastern bank/shore of Brydon Creek where it forms narrow lakes, about 600 metres southwest of Butterfly Lake. The samples were collected in the contact area of the ultramafic intrusion with Stikine rock. Samples varied from hornblendite, skarned rock, to tuffs(?), to dikes of diorite and felsic composition. Sample PHK-02, south of the hornblendite and north of the skarned rock, was described as a calcite vein with epidote alteration, carrying pyrite and malachite; this sample graded 0.18 per cent copper and 1.2 grams per tonne silver (Assessment Report 19099). Sample PHK-03, taken from the skarned rock containing pyrite, chalcopyrite, malachite and azurite and large euhedral garnets and diopside crystals, assayed 0.125 per cent copper and 0.8 gram per tonne silver (Assessment Report 19099). Sampling and mapping were also completed southeast of the Butterfly Lake showing and east of the Upper Brydon showing, on the north and west flank of Butterfly Mountain (Assessment Report 19906). Twelve of the Butterfly Mountain samples yielded anomalous copper values.

In 1990 Shellex carried out 20 man-days of fieldwork on the Phacops property (RB 23-25 and 29 claims). They collected a total a total of 37 rock, 81 soil and 17 silt samples. Most of the soil samples were taken (roughly) along a contour line partially around Phacops Mountain, west of Butterfly Lake (Figure 4, Assessment Report 21148). Other rock and silt samples were taken much farther south of the Upper Brydon showing on the RB 23, 24 and 29 claims.

For related information see the MINFILE showing labelled Butterfly Lake, about 1 kilometre to the northeast the Upper Brydon showing.