NO. 5 PRE-DEVONIAN PALEOZOIC FORMATIONS 2I3 



Lot B. a Stromatoporoid Feet 



Cyrtodonta f sp. 

 Spyroceras sp. 

 Actinoceras ? siphuncle 

 Trilobite fragments 

 " These two lots, though but a couple of feet apart, have an 

 entirely different matrix as well as a different fauna. Lot A is a 

 typical LIpper Ordovician Beaverfoot fauna. Lot B represents a 

 Richmond horizon, but both matrix and fauna differ from any other 

 Richmond section submitted." 

 188 feet from top 

 Halysites n. sp. (a) 

 Streptelasma n. sp. 



Rhynchotrema n. sp. (a) nr. R. capax 

 Plectambonitcs cf, saxciis (Sardeson) 



Protokionoceras ? n. sp 213 



9. Calcareous sandstone, Crinoid stems observed at top 25 



Part of section measured 759 



Mr. Walker adds : " The calcarecnis sandstone at the base rests 

 on the Wonah quartzite." 



It is evident from this section that Nos. 7 to 9 inclusive [368 feet 

 (112.2 m.)] represent the Beaverfoot formation, and that No. 5 is at 

 the base of the Brisco formation. The Virginia sp. in No. i belongs 

 in the Brisco fauna, while the faunules of 7 and 8 belong in the 

 Beaverfoot. 



Dr. Edwin Kirk and I had no difficulty in finding a line of demar- 

 cation between the two formations in the Stanford Range north of 

 Sinclair Canyon and between Sinclair and Stoddart Canyons and 

 on Sabine Mountain. Dr. Kirk spent several weeks studying and 

 collecting from the Silurian and did not note the presence of passage 

 beds or intermingling of the faunas of the Beaverfoot and Brisco 

 formations. Even where there appear to be transition beds such as 

 Mr. Walker noted, it is highly probable that a critical study at such 

 localities will reveal differences not noticeable in a brief field inspection. 



Brisco Formation. Walcott, 1924' 



Type locality. — Westward-facing cliffs of the Brisco Range above 

 the Columbia River Valley between Harrowgate and Sinclair Canyons, 

 British Columbia. 



Derivation. — From Brisco Range. 



Character. — Dark gray, rough-weathering, more or less siliceous 

 magnesian limestones, with a belt of black argillaceous and calcareous 

 shales 300 feet (91.4 m.) above the base of the formation. 



^ Smithsonian Misc. Coll., Vol. 75, No. i, 1924, p. 47. 



