12 



SMITHSONIAN MISCELLANEOUS COLLECTIONS 



VOL. 75 



Silurian graptolite beds. — In the upturned Silurian, Brisco bluish black lime- 

 stones about S miles (8 km.) below Sinclair Pass on the south side of the 

 canyon, an intercalated band of black argillaceous shale carries an abundant 

 graptolite faunule which Dr. Rudolf Ruedemann correlates with the Clinton 

 formation graptolite faunule of the Silurian, which places it above the Beaver- 

 foot (Richmond) coral fauna and in the Brisco limestone of the Silurian. Dr. 

 Kirk located this shale in Sinclair Canyon section at about 300 feet (91.4 m.) 

 from the base of the Brisco limestone formation. We did not find it elsewhere 

 either to the north or south. 



Fig. 3. — Illustration of occurrence on surface of shale of Silurian graptolites 

 in Sinclair Canyon. 



Monograptus cf. Spiralis Geinitz 

 Monograptiis sp. 



Dr. Ruedemann reported on the graptolites as follows : 



The faunule consists of: . 



Monograptus sp. nov. This form is closely related to Monogr. spiralis 

 (Geinitz). 



Monogr. marri Perner. This form is practically identical with the European 

 species. 



Retiolites (Gladiograptus) geinitsianus Barrande, which is the same as R. 

 venosus Hall from our Clinton. These three species, M. spiralis, marri and 

 Retiolites geinitsianus, are all Gala-Tarannon forms of Great Britain and occur 

 also in Bohemia, etc. The faunule from Sinclair Canyon in British Columbia 

 is hence fairly safely correlated with that of the Gala-Tarannon beds of Britain, 

 and also with the Clinton graptolite shale of New York. (Williamson shale.) 



