Mesozoic mid Canozoic Geology and P alee ontology. 191 



Alfred' R. C. Selw^-n* explored the couiitiy north and northeast of 

 Fort George near the 5-4th parallel. The exploration was almost wholl}^ 

 within the Arctic watershed, and the basin of Peace river. From "The 

 Fork" — Smok}' river — up to Dunvegan, and thence to about five miles 

 below Hudson's Hope, the rocks which are exposed along Peace river 

 are mesozoic; they consist of dark, earth}' shales, in parts character- 

 ized by numerous bands and septarian nodules of clay iron- 

 stone, many of which inclose large Ammo7iites, and they are also 

 associated with sand}^ calcareous layers, holding other Cretaceous 

 fossils, among which a species of Inoceramus is tolerably 

 abundant, while in the dark argillaceous shales the scales of fishes 

 are frequently observed. Descending Peace river, these dark 

 shales are first seen at about six miles below Hudson's Hope. Thej^ 

 are nearl}'- or quite horizontal, and are exposed at intervals between 

 this point and Fort St. tTohn, in clifl's which rise almost perpendicu- 

 larl}' from the water to heights of 50 or 100 feet. Near where the}^ are 

 first seen, the hills at a little distance back rise to 500 or 600 feet, and 

 toward their summits present cliffs in which some thick beds of brown 

 fine-grained sandstone crop out. About a mile below St. John, on the 

 left bTink, a section is exposed nearl}- 700 feet in thickness. These 

 rocks are exposed at intervals down to The Fork, and also on Smoky 

 and Pine rivers. On the latter stream the exposed thickness is esti- 

 mated at 1,700 feet, and contains four thin seams of bituminous coal. 



Prof. George M. Dawson, who explored the country between the 52d 

 and 54th parallels, in British Columbia, found the equivalent of the 

 Shasta Group in the vicinit}^ of Tatla3'oco lake. Along the eastern 

 shore of the lake these rocks overlie those of the porph^-rite series. 

 The}' dip eastward, or away from the anticlinal axis, in which the lake 

 lies, and form, at a short distance from its eastern margin, a rampart- 

 like wall of mountains, from 2,000 to 3,000 feet high, and twelve miles 

 in length. The rocks are compact, bluish-gray quartzites, or hard sand- 

 ,stones, and conglomerates of all grades in regard to size of particles, 

 associated with blackish.or dark colored slaty and shal}' beds, which 

 recur frequentl}^ at different horizons. The thickness of the entire 

 Qretaceous series on the east side of Tatlaj'oco lake is estimated at 

 7,000 feet. Their geographical extension is also great. He regarded 

 the Jackass Mountain Group as the equivalent of the Shasta Group 

 of California. 



"■'■' Geo. Sur. of Canada. 



