Smithsonian miscellaneous collections . r fossil coral beds above the whitequartzite of the Richmond transgression (see fig. 18) were found inthe upper portion of Sinclair Canyon, and not far away black shalesfull of Silurian graptolites (fig. 19). Lower down the canyon thinbedded gray limestones yielded fossils of the Mons^ formation notunlike those so abundant at the head of Clearwater Canyon, 73 miles( km.) to the north, and Glacier Lake, miles ( km.) Smithsonian Misc. Coll., Vol. 72, No. i, p. 15, 1920. i8 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 74 north. It is evident t
Smithsonian miscellaneous collections . r fossil coral beds above the whitequartzite of the Richmond transgression (see fig. 18) were found inthe upper portion of Sinclair Canyon, and not far away black shalesfull of Silurian graptolites (fig. 19). Lower down the canyon thinbedded gray limestones yielded fossils of the Mons^ formation notunlike those so abundant at the head of Clearwater Canyon, 73 miles( km.) to the north, and Glacier Lake, miles ( km.) Smithsonian Misc. Coll., Vol. 72, No. i, p. 15, 1920. i8 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 74 north. It is evident that in the ancient and narrow Cordilleran Seathat extended from the Arctic Ocean 2,000 miles (3,218 km.) or moresouth between the coast ranges of the time and the uplands of thecentral portion of the North American continent, there was a simi-larity of Lower Paleozoic marine life along the shores and in itsshallow waters. Evidences of this and of strong currents and per-sistent wave action occur all the way from central Nevada to Mount. Fig. 19.—Graptolites that flourished on the muddy bed of the sea inSilurian time. The coiled form Monograptus convolutus Hisinger is foundboth in Europe and America. The straight form is very abundant in someof the partings of the shale. Locality: Sinclair Canyon about miles ( km.) above Radium HotSprings, in cliff on south side of Banfif-Windermere motor road, BritishColumbia, Canada. Robson in British Columbia. The record of the marine life anddeposits of mud and sand is most complete, and it has been great sportrunning down the various clews that have been encountered fromtime to time. The lower Sinclair Canyon opens out into the Columbia RiverValley through a narrow canyon eroded in the upturned and faultedlimestones. Some conception of the character of the canyon may beobtained from figures 21-23. NO. 5 SMITHSONIAN EXPLORATIONS, ig22 19
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