tain in black silicified carbonate. It contains 10 to 20% white elongate objects suggested by J.E. Klovan and F. Stoakes (personal communication, 1978) to be possibly Amphipora which range from Late Silurian through the Devonian. The second locality is 850 m north of the mouth of Limestone Creek (52°59’6.3’’N, 121°11’3.7’°W; GSC Locality C-82851) where conodonts were extracted from a thin black micritic limestone bed in black slate. The rocks are exposed near the base of the cliff along the Cariboo River bank. The conodonts were identified by T.T. Uyeno as fragments of the Poly- gnathus varcus Stauffer group of Klapper et al. (1970). He assigned them to the range Lower Polygnathus varcus subzone to Lowermost Polygnathus asymmetricus zone, that is Late Middle Devonian. In summary the informal units of the Black Stuart Group range from Late Ordovician to Late Devonian and possibly younger. Upper Ordovician graptolitic pelite may be separated from the Lower Devonian chert-carbonate unit by a Silurian unconformity. The Middle and Late Silurian brachiopods described by Lenz (1977) may be from a limestone unit locally preserved beneath the Lower Devonian chert-carbonate unit. The black pelite overlying the chert-carbonate unit could span the interval from Early to Late Devonian. The sandstone unit is Upper Devonian or younger, because it overlies the black pelite unit. The oldest rocks of the Black Stuart Group, the grap- tolitic slates of the black pelite unit, correlate with Ordo- vician graptolitic pelites of the Road River Formation from northern British Columbia. Gabrielse (1975, p. 11) reported southernmost Road River facies equivalents in the Fort Grahame map area. Northward from Fort Grahame map area Road River Formation equivalents can be traced into the Selwyn Basin of Yukon Territory (Gabrielse, 1975). Detailed stratigraphy of Road River Formation has recently been described by Cecile and Norford (1979) for a part of northern British Columbia and by Gordey (1978, 1979) for the Summit Lake area in Northwest Territories and Yukon. In southern British Columbia correlations are less certain. The Lower Devonian chert-carbonate unit could cor- relate with Lower Devonian carbonates of northern British Columbia. The Muncho-McConnel Formation (Taylor and Stott, 1973; Taylor et al., 1979) and related calcareous sandstone and limestone debris flows (Taylor et al., 1979) in the Ware map area and the ‘‘tapioca’”’ sandstone sequence in McDame and surrounding area (Gabrielse, 1963) are examples of possible correlative quartz-sand-rich carbonate of the Lower Devonian. In contrast to them the chert-carbonate unit has only local examples of calcareous quartz sand and sandy limestone from Limestone Creek and one locality on Anderson Ridge. Besides quartz the Limestone Creek outcrop also has chert breccia, dolostone breccia, cherty pelite and rounded sandstone clasts which is not characteristic of the Lower Devonian occurrences noted in northern British Columbia. 26 The younger black pelite unit may range into the Mis- sissippian and is in part correlative with the Earn Group (equivalents of which are informally called the ‘‘black clastic’’) of basinal facies throughout northern British Columbia and Yukon. The Amphipora — bearing Middle Devonian black fetid carbonates of the McDame Group (see Gabrielse, 1963) may be in part correlative with a silicified amphiporal carbonate found 2.8 km southeast of Black Stuart Mountain. The age of the sandstone unit is not directly known, but is probably Upper Devonian or younger because it overlies one of the conglomerate facies of the Guyet Formation. Its correlation outside the area is unknown. Waverly Formation The name Waverly was first used geologically by Johnston and Uglow (1926) and was subsequently aban- doned by Sutherland Brown (1957). The name is repro- posed for a formation of volcanic rocks found underlying the conglomerate of the Guyet Formation and which are well developed on the southwest slopes of Waverly Moun- tain. Sutherland Brown (1957,1963) included these vol- canic rocks in the Guyet Formation but did not give them any status. The Waverly Formation consists of schistose calcare- ous basaltic agglomerate and flows, pyroclastics, pillow basalt and minor breccia, and chlorite-rich quartz siltite. It is the only volcanic unit recognized from the Cariboo Terrane of the map area. The calcareous agglomerate, flows and pyroclastics distinguish the Waverly Forma- tion from volcanic rocks of the Antler Formation of the Slide Mountain Terrane. The Waverly Formation underlies a narrow belt extending from Summit Creek southeastward to near Black Stuart Mountain. The reference area of the Waverly Formation is in the area of Waverly Mountain where the unit is the most diverse and has a large areal extent. It was mapped by Johnston and Uglow (1926) as part of the Waverly Formation, which included rocks now mapped as Antler Formation. Sutherland Brown (1957) mapped it as part of the Guyet Formation, and later in the Black Stuart Mountain area as part of the Midas For- mation (Sutherland Brown, 1963). Campbell et al. (1973) included the Waverly Formation as part of the Black Stuart or Guyet Formation. The thickness of the Waverly Formation, where present, varies from approximately 2 to 40 m. The lower contact is sharp and suspected to be conformable above the black pelite unit of the Black Stuart Group. The basalt of the Waverly Formation is characteris- tically pyroclastic and carbonate-rich. In most areas the basalt is a schistose calcareous greenstone with little indi- cation of original texture or mineralogy. It consists of a foliated matrix of chlorite, semi-opaques, sericite and epidote supporting 0.5 to 4 mm augen-shaped knots of dark grey to black calcite or dolomite (Table 8). Agglo- merate with basalt clasts (pebble to boulder size) occurs