The North Blue River is a mica showing hosted in pegmatite, 5 kilometres northwest of Blue River.

The Canoe River map area is predominantly underlain by a sequence of Hadrynian metasedimentary strata, belonging to the Windermere Supergroup (Miette, Horsethief Creek and Kaza groups) and their basement gneisses. Lithologies common to the area include semipelite, psammite, grit, marble and calc-silicate.

Little information is available for this showing which was first mentioned as one of several occurrences of large books and crystals of mica hosted in pegmatites in the Canoe River area (Minister of Mines Annual Report 1902).

A large pegmatite body was mapped in 1983 as part of a field study of the structural evolution and metamorphism in the Blue River area (Geological Survey of Canada Paper 84-1A, pp. 91-94). The description of pegmatite in the Blue River area given in 1902 is assumed to be part of this body or an apophyses of it.

The ages of pre and post phase three deformation pegmatites has been determined to be 154+/-6 Ma and 125+/-7 Ma respectively from pegmatites in the Cariboo Mountains west of Valemount (Geological Survey of Canada Paper 90-1E, pp. 71-80).

Large masses of pegmatite were observed interbanded with micaceous schists of the Hadrynian Horsethief Creek Group. Albite or oligoclase feldspar and a vitreous quartz comprise the major principal constituents (Minister of Mines Annual Report 1902). Other pegmatites in the Canoe River area contain garnet, tourmaline, kyanite, beryl and apatite as accessories (Minister of Mines Annual Report 1920). Some pegmatite bands and masses are over 30 metres wide and 60 metres long. It is these pegmatites in which large crystals of commercial sheet mica are found, geological and geochemical conditions permitting (Minister of Mines Annual Report 1902).