walcott.] SUMMARY — CANADIAN EXTENSION. 327 



Attention was called to the resemblance of the strata of the Bow 

 River series to those of the Big Cottonwood Canon section of the 

 Wasatch Mountains of Utah, by Dr. G. M. Dawson, in 1885. A com- 

 parison of the two leads to their correlation as equivalent formations, 

 on the evidence of their litbologic characters and stratigraphic position 

 and the fact that the Olenellus fauna occurs in the upper portion of 

 each section. In his paper of 1889 Mr. R. G. McConnell 1 states that 

 specimens of Paradoxides and other fossils were found at the junction 

 of the Bow Eiver and the superjacent Castle Mountain group. A col- 

 lection made at this horizon was sent to me for examination, and I 

 identified Olenellus sp. undt., Protypus senectus, and a species of Ptychop- 

 aria undistinguishable from P. adamsi of the Olenellus zone of Vermont. 

 The occurrence of the Olenellus fauna at this horizon and of Olenellus 

 gilberti, 3,000 feet lower in the section, corresponds to the great range 

 of the fauna in the New York and Vermont sections. 



The Castle Mountain group, in the Castle Mountain section, com- 

 mences with a thin band of shaly limestone, above which come 1,500 

 feet of massive dolomites. These are subjacent to some yellowish, 

 compact, impure dolomites, above which 300 feet of reddish shales oc- 

 cur subjacent to several hundred feet of shaly magnesian limestones. 

 The Mount Stephen section shows about 5,000 feet of beds, consisting 

 mainly of heavy dolomites, with shaly bands at intervals. One of these, 

 occurring at the base of the formation and another about 2,000 feet 

 higher up, are rich in trilobites. 2 



Reference has already been made to the fauna occurring at the base 

 of Castle Mountain. From the next fossiliferous zone, 2,000 feet up in 

 the section, the following species have been obtained: 



Lingulella macconnelli. Agnostus interstrictus. 



Crania? colurobiana. Oleuoides nevadensis. 



Kutorgina prospectensis. Zacantboides spinosus. 



Acrotreta gemma, var. depressa. Ptychoparia cordillerao. 



Liiinarsonnia sagittalis. Bathyuriscus howelli. 

 Ortbisiua alberta. (K.) dawsoni. 



Platyceras romingeri. Kaslia stephenensis. 



Hyolithellns micans. Ogygopsis klotzi. 



Where the line between the Cambrian and the Lower Silurian (Ordo- 

 vician) is to be drawn in the Castle Mountain group is still undeter- 

 mined. The discovery of a specimen of Ptychoparia oweni in the 

 debris washed down by the Cascade River from the Cascade Mountains 

 indicates the presence of the Upper Cambrian fauna in this region, and 

 it is not improbable that it will be found in the Castle Mountain or 

 Mount Stephen section. 



1 Notes on the geology of Mount Stephen, British Columbia. American Geologist, vol. 3, 1889, pp. 

 22-25. 



2 Report on the Geological Structure of a portion of the Rocky Mountains, with a section. GeoL 

 Surv. Canada, new ser. 1886-87, 1887, pp. 24-291). 



