152 CONTRIBrTIONS TO CANADIAN PAL/EONTOLOGY. 



Eiver, B.C., from a mountain six or seven thousand foet high above sea 

 level, Mr. Soues (per Mr. T. Blwyn), 1886". South Fork of Quesnel 

 Eiver, near the foot of Quoanel Lake, A. Bowman, 1886. 



Porcupine Eiver, N.W.T., in latitude 67° 8' N. and longitude 137° 

 47' W. ; also Yukon Eiver, Alaska, eight miles below the Antoine 

 Eiver, in latitude 65° 15' N. and longitude 141° 40' W. ; E. G. Mc- 

 Oonnell, 1888. Extremely abundant at most of these localities. 



The specimens from each of these localities are undoubtedly con- 

 specific with the Aucella Piochii of Gabb from the Shasta Group of 

 California, and with the fossils from the Cretaceous rocks of Alaska 

 which Dr. C. A. White regards as a variety of the A. concentrica of 

 Fischer. In the Lethasa Eossica, however, Bichwald has expressed 

 the opinion that A. concentrica is not specifically distinct from the A. 

 Ilosquensis of von Buch, and the writer has long been convinced that 

 A. Piochii also is only an inconstant varietal form of A. Mosquensis. 

 The names A. concentrica and A. Piochii have been given with the view 

 of distinguishing comparatively broad specimens whose valves are 

 almost equally convex, from the typical A. Mosquensis, which is 

 ■narrowly elongated and whose right valve is flatter than the left, but 

 a study of some three or four hundred Aucellffi from various localities 

 in British Columbia has led to the conclusion that the most dis- 

 similar examples are connected by every kind of intermediate grada- 

 tion. A careful comparison of Dr. White's illustrations of the Alaskan 

 fosBsils which he refers to A. concentrica with Bichwald's figures of 

 specimens of A. Mosquensis from Alaska and the Aleutian Islands, will 

 be suflicient to shew how difficult if not impracticable it is to dis- 

 criminate between these nominal species. 



By some writers the Aucella-bearing deposits of Eussia have been 

 regarded as of .Jurassic age, and by others as of Cretaceous. D'Orbigny 

 refers them to his " i5tage Oxfordien," Trautschold and Eudolph Lud- 

 wig to the Titbonic system of Oppel, and Eichwald to the Upper 

 Neocomian. Ever since 1875, the year in which Aucellte were first 

 discovered in British Columbia, the present writer has been convinced 

 that the rocks in which they are the j)revalent fossil, in that province 

 as well as in California, are of Cretaceous age. In the Transactions of 

 the Eoyal Society of Canada for 1882, the opinion was expressed that 

 these rocks are pi'obably of the horizon of the Upper Neocomian. At 

 the time that this paper was written, not more than eight species in a 

 sufficiently perfect state for identification or description had been 

 found associated with the Aucellse in British Columbia, and of these, 

 only two (viz., Ancyloceras Remondi and Syncylonema MeeJciana), besides 

 the Aucella, were recognized as occurring also in the " Lower Shales 

 and Sandstones, or Subdivision C" of the Cretaceous rocks of the 



