The sedimentary environment of the Eaglesnest is interpreted to be the same as the other quartzite-pelite sequences of the Snowshoe Group; debris flow transition- al to turbidite. The Eaglesnest succession is undated and thought to be Paleozoic only because it overlies the Harveys Ridge succession, assumed to be Paleozoic. Correlation of the Eaglesnest succession with units beyond the map area was not attempted, but in a general way it may relate to the grit-pelite sequences of the Eagle Bay Formation of south- central British Columbia. Downey succession The Downey succession is composed of micaceous quartz- ite, phyllite, marble, limestone, calcareous quartzite and tuff. The unit is characterized from others of the Snow- shoe Group by its abundant marble and tuff. The quartz- ite commonly is brown weathering because of abundant porphyroblasts of ankerite and siderite. The Downey succession underlies a narrow belt from Big Valley Creek in the north to the head of Cariboo Lake in the south. The rocks were previously mapped as Baker member of the Richfield Formation by Hanson (1935), Upper Snowshoe Formation by Holland (1954) and Sutherland Brown (1957), as undifferentiated Snowshoe Formation by Campbell (1961) and Campbell et al. (1973), and as the Downey Creek succession of unit 5 by Struik (1982a). No type section is assigned for this unit. Reference exposures are the roadcut along Downey Creek and those along Grouse and Cunningham creeks. The thickness of the succession is unknown, but is estimated to be more than 150 m. The lower contact is poorly understood. At Mount Barker the Downey succession overlies the Harveys Ridge in apparent stratigraphic continuity. A similar relation- ship is implied on Harveys Ridge although the contact is not seen. The tuff and carbonate horizons on Mount Barker are near the basal contact, similar to the situa- tion along Cunningham Creek. It is an apparent contra- diction that both the Downey and Eaglesnest successions stratigraphically overlie the Harveys Ridge; possibly because they are laterally equivalent, or one or the other is unconformable on the Harveys Ridge. Quartzite and phyllite of the Downey succession are grey, olive and brown, weathering grey and olive. Some areas of phyllite are green and brown where associated with possible tuffaceous rock. The quartzite-phyllite sequences may be altered to light grey and white in areas of hydrothermal activity such as the gold deposits near Wells and Barkerville. The quartzite is poorly sorted, micaceous and ranges in grain size from fine to coarse. It consists of 50 to 80% quartz (glassy clear, light grey to grey and minor blue), up to 10% feldspar and minor zircon. Secondary minerals include the matrix of white mica and chlorite and accessory limonite, pyrite, anker- ite, siderite and tourmaline. Minor quantities of sphene, garnet, apatite and epidote appear in heavy mineral sepa- rates. The quartzite is locally calcareous. The phyllite con- sists of quartz silt and fine white mica and chlorite. Acces- sories commonly include ankerite, siderite, pyrite and limonite and locally chloritoid and biotite. Green chlori- tic phyllite contains abundant epidote and is considered to be at least in part of volcanic origin. In many places this phyllite is thinly interbedded with caramel-brown and purple phyllite in 10 to 30 m sequences commonly asso- ciated with marble. The limestone and marble are grey and interlamin- ated grey and white. Crystal sizes range from 0.3 to 2 mm. The carbonate is everywhere strongly foliated apparently due to shear. It is commonly interlayered with green and grey phyllite and overlies, and is interbedded with, vol- canic tuff. It is this interbedding of tuff and marble that distinguishes the Downey from other units of the Snow- shoe Group. The Downey carbonate is the productive host for the replacement gold-bearing pyrite of the Barkerville gold belt. The volcanic rock of the Downey is only poorly stud- ied consisting primarily of tuff. Diorite sills were described from the Cariboo Gold Quartz Mine by Skerl (1948). Diorite is also found interlayered with the lime- stone marble along Cunningham Creek and at Mount Barker. Although labelled as diorite these rocks are more likely dioritic tuff. Beds of the quartzite-phyllite sequences range from to 150 m thick. Graded bedding exists but is not com- 10n. Contacts between the quartzite and phyllite are generally sharp. The quartzite in places grades into mar- ble and phyllite sequences. Contacts between marble and phyllite are mostly gradational and with the tuff are sharp. More detailed descriptions of the Downey succes- sion in the vicinity of the Mosquito Creek Mine wer given by Alldrick (1983). : The depositional environment of the Downey is con- sidered to have been a marine shelf periodically inundated with clastic debris in the form of turbidites and debris flows. The carbonate and pelite are representative of low clastic input and the tuff of minor volcanic debris shed from a distant source. Age and correlation. There are two occurrences of microscopic organic remains within the Downey; one in calcareous quartzite along Sugar Creek (Fig. 43), the other in dark grey sandy limestone on the 2200 logging road where it crosses Big Valley Creek. The fossils were determined by B.L. Mamet (University of Montreal) to be: GSC Locality C-102829 (lats-53°10723"2;Jeng. 1 21P4US7") Silicified kamaenid algae or halysisid algae GSC Locality C-102827 (lat. 53°10’37’’, long. 121°34’59’’) Algae Probable ostracod? Echinoderm Bryozoan 59