on Cunningham Formation in the north bank of Separation Creek 500 m; Shepherd Creek, north-northeast of Wells. The Cunningham Formation limestone is predomi- nantly grey weathering, grey to cream or greenish grey, and medium to finely crystalline. It is best preserved at the base of the formation on the east end of Kimball Ridge where it retains a micritic texture and is thin bedded as defined by carbonaceous pelitic lamellae. Limestones throughout the remainder of the section display the pro- found changes in texture usually found throughout the map area. Micritic limestone grades to very finely crystal- line limestone to a coarsely crystalline marble. Colour changes follow most variations in crystal size. The dark- est limestone is micrite and with increasing crystal size it varies from dark grey to creamy white. Marbles and moderately crystalline limestone commonly are tinged with green, a colour rarely found in carbonates of the Mural Formation. Increased recrystallization of the micri- tic limestone generally correlates directly with increased stratigraphic and structural depth but is also very much controlled by tectonism. Cunningham Formation is near- ly completely marble in its southeasternmost outcrops where it is structurally the lowest. Marble also occurs throughout the map area but is usually associated with faulting and tight folding. Commonly found within the limestone and marble are knots of dolomite crystals. They are usually from 0.5 to 2 mm across and account for 1 to 10% of the limestone, but locally may be more abun- dant. The dolomite is usually ferroan, imparting a pink- ish speckling where the iron has become oxidized. A good example of this type of carbonate is found in the cliff banks of Sixbee Creek, where the flow changes from northerly to southerly. Young (in Campbell et al., 1973) used ferroan dolo- mite content as a method of distinguishing Cunningham Formation from Mural Formation limestones in the Cari- boo Mountains. This criterion has not proven useful because it cannot be demonstrated to be confined to the Cunningham Formation. For example, on the south slope of Kimball Mountain Mural Formation limestone is spotted with dolomite near a small fault. The dolomite is not ferroan at this locality, but ankerite and ferroan dolomite are recorded from every other formation of the Cariboo Group. Finely crystalline limestone commonly displays mod- erate grey and light grey to white banding (0.5 to 2 cm) which is found in all the limestone of the area and is not restricted to the Cunningham Formation. The bands com- monly are layer-parallel and isoclinally folded, yet are parallel to regional bedding trends and most can be assumed to mimic original bedding. Dolostone is best developed along Roundtop Creek and its junction with Cunningham Creek. There very coarse dolostone is associated with quartz veins with minor amounts of galena. It varies from creamy white to light grey and moderately crystalline, sugary textured to very coarsely crystalline. Where a small percentage of 12 the dolomite is ferroan the dolostone is buff or light brown. Dolostone in the cliffs overlooking Lostway Creek occurs along faults. The Lostway Creek thrust, which puts Cunningham Formation onto Mural Forma- tion, has a glide zone some | to 3 m thick composed of sugary textured white dolostone. The irregular distribution of dolostone and limestone is best explained by local controls of dolomitization and is not a regional phenomenon resulting from paleoenvi- ronmental factors. Pore spaces that formed during ini- tial dolomitization were later infilled with anhedral dolo- mite indicating redistribution of carbonate material. The dolomitization process can be seen to cut across bedding, forming irregular pods of dolostone in limestone. The best example of this is where Mural Formation is faulted against Yankee Belle Formation at the head of Round- top Creek. Young (in Campbell et al., 1973, p. 37) reported “‘pisolites, oolites, pellets, algal-coated complex grains, intraclasts and unidentified ovoid grains’’ from the Cun- ningham Formation limestone of the Cariboo Mountains. Record of these features is scanty. The dolomite knots may be dolomitized remnants of some type of pelletoid (see Sutherland Brown, 1957, 1963). Table 3. Reference section of Cunningham Formation on Kimball Ridge (location; 52°55'10’N, 121°00’10’’W). Thickness in metres Unit Lithology Unit Above base 4 Limestone to fine marble, grey to light greenish grey, moderately eiysialiie tA SSeS 9 360 COVELCG eco ee, citer ene eee 18 351 3 Limestone, grey and buff mottled weathering grey and light orange brown, colours are streaked and patched, upper section is spotted with 3% orange ferroan GONG = fo eee 4 333 Covered, probably limestone ..... 90 329 2 Limestone, moderately light grey weathering grey, moderately fine to finely. crystalline... So : 239 Covered, probably limestone ..... 100 232 1 Limestone, grey weathering grey to dark grey, fine grained; interleaved with films of silvery grey phyllite in 3 to 5 cm beds, 1%, 1 to 2 mm pyrite cubes disseminated SENN pie 92 wi Sate Ey os. 12 132 Goveted. 22 Skies 120 120 Underlying beds; interbedded brown-weathering dark grey lime- Stone, and black phyllite of Isaac Formation.