The Lexington Mountain region is underlain by a series of metamorphosed Cambrian to Devonian sedimentary and volcanic rocks of the Lardeau Group which overlies the Lower Cambrian Badshot Formation in the east. The predominant structural features in the area are northwest trending and plunging overturned folds and regional semiconcordant to concordant faults. The strata within these structures are steeply east dipping with a variable plunge to the northwest.

Three distinct northwest striking limestone-chlorite schist contact zones spaced at roughly 1 kilometre intervals cross the property. The Index Formation (Lardeau Group) hosts similar mineralization within these zones and may represent either folded repetitions of the same contact or stratigraphic repetitions of similar depositional environments. The mineralization occurs as both disseminated and massive zones of galena, pyrite and sphalerite associated with dolomitized limestone and silicification invariably developed with siderite-rich zones containing hematite and magnetite localized along the limestone-chlorite schist contacts.

At the Morning Star showing near the contact of a green chlorite schist and siliceous blue limestone containing numerous quartz and calcite stringers is a vein 2.1 metres wide striking 310 to 320 degrees, dipping 62 to 75 degrees east. The vein is conformable to the enclosing rocks and contains pyrite, galena and sphalerite in a gangue of limestone and quartz. The vein is highly oxidized at surface with pyrite and galena leached out but the zone of oxidation only extends a short distance below the surface. The vein has been traced by numerous opencuts and trenches. A crosscut adit was begun in 1914 to cut the vein at a vertical depth of 9 metres and reached 21 metres length.

Northeast of the hangingwall chlorite schist, about 61 metres farther up the hillside, a band of crystalline limestone hosts another vein which has been opened by a series of surface trenches and a short prospecting drift (Minister of Mines Annual Report 1914).

This area was originally explored in the late 1800s and early 1900s when prospectors discovered widespread precious and base metal mineralization.