628 INDEX TO THE STRATIGRAPHY OF NORTH AMERICA. 



If the identifications ia the present paper be correct, it would appear that nine of Meek 

 and Hayden's species, from the Jurassic rocks of Dakota, are found also in the Coast Range of 

 British Columbia. These are: 



Gryphsea calceola var. nebrascensis. 

 Camptonectes extenuatus. 

 Eumicrotia curta. 

 Modiola (Volsella) formosa. 

 Modiola (Volsella) pertenuis. 

 * * * 



Grammatodon inornatue. 

 Astarte fragilis. 

 Pleuromya subelliptica. 

 Planorbis vetemus. 



Trigonia dawsoni and Astarte ventricosa, from the Iltasyouco River, are also found in the 

 Jurassic rocks of the western slope of the mountains in Nevada ; and it may be that there is no 

 physical or geographical break between the coast range of British Columbia and the Sierra 

 Nevada. Mr. Gabb has pointed out that the Jurassic fossils of Nevada are probably of the age 

 of the Lias, and some of the Iltasyouco lamellibranchs, as has already been stated, are barely 

 distinguishable from European Liassic species. On the other hand, the few ammonites col- 

 lected by Mr. Dawson, so far as very fragmentary specimens enable one to judge, appear to be 

 conspecific for the most part with weU-known forms from the English Inferior Oohte, though 

 one, which has been doubtfully referred to PerispTiinctes anceps, may indicate a horizon as high 

 as the Oxford Clay or Coral Rag. On the whole, however, the evidence, as far as it goes, is in 

 favor of the supposition that these fossils from British Columbia belong to the lower rather than 

 to the upper part of the Jurassic series. 



Subsequently Whiteaves ®^* modified this conclusion in favor of a later age for 

 the rocks in question. He says : 



Certain rocks described by Dr. Dawson in the report of progress of the Geological Survey of 

 Canada for 1876-77, and there referred to as the "Porphyrite series," occur on Sigutlat Lake and 

 the. Iltasyouco River, which flows from Sigutlat Lake into the Dean or Salmon River. The 

 fossils collected from these porphyrites were reported upon provisionally by the writer in an 

 appendix to Dr. Dawson's report. They were then regarded as possibly of Jurassic age, on 

 account of their resemblance to the fossils of the so-called Jurassic rocks of the Black HUls of 

 Dakota, but are now believed to be Cretaceous. 



The collections of fossils that have been made from the Cretaceous rocks at Quatsino Sound, 

 Vancouver Island, in 1878 and 1885, and at various locahties off the coast or on the mainland 

 of British Columbia between 1875 and 1888, have led to the conclusion that the Aucella-bearing 

 rocks and Jackass Mountain series of that province are not older than but of about the same 

 age as the Queen Charlotte Island formation, and that the porphyritic rocks of Sigutlat Lake and 

 the Iltasyouco River are of the same age and not altered Jurassic sediments. 



N 8-9. QTJEEN CHARLOTTE ISLANDS. 



The Cretaceous or coal-bearing rocks of Graham Island, the northern member 

 of the Queen Charlotte group, are described by Ells,^^^'' who, however, confines 

 his account largely to local details and refers to Dawson for a general discussion. 

 Dawson,^^^^ following Richards on, "'''^^ distinguished the following strata: 



Feet. 



A. Upper shales and sandstones 1,500 



B. Coarse conglomerates 2,000-3,000 



0. Lower shales with coal and iron ore 1,800-5,000 



To these he added : 



Feet. 



D. Agglomerates of volcanic origin 3,500 



E. Lower sandstones 1,000? 



