261 



The Camptonectes bellistriatus of Meek and Hayden, from the Black 

 Hills of Dakota, looks more like a Cretaceous Amusium or Camptonectes 

 than it does like the true Pecten lens of Sower by, which latter species 

 the writer has had abundant opportunities of studying in the field, in 

 the Middle and Lower Oolites of the midland counties of England. 

 Camptonectes extenuatus of Meek and Hayden, as figured by Prof. E. P. 

 Whitfield in the " Paleontology of the Black Hills of Dakota," bears a 

 remarkably close resemblance to the C. curvatus of G-einitz, from the 

 Cretaceous rocks of Southern India, as described and illustrated by 

 Stoliczka. 



The Modiola (or Volsella) formosa of Meek and Hayden belongs to a 

 persistent and recurrent section of that genus, which ranges from the 

 Jurassic epoch into the recent period, and which is represented in 

 northern seas by the Modiolaria nigra of Gray. 



The very variable guards of Belemnites from the Black Hills and 

 elsewhere, which Mr. Meek described provisionally under the name B. 

 densus, may represent two or three species rather than one, and 

 neither of them seem to present any special characters by which they 

 can be distinguished as Jurassic species rather than Cretaceous. 



Oxytoma mucronata, Meek, for reasons already stated on pages 238 

 239, appears to be more nearly related to the 0. Corneuiliana of 

 d'Orbigny, from the French Neocomian, than to the 0. Munstyri, 

 Goldfuss, of the Jurassic, and the typical form of the Pleuromya sub- 

 compressa of Meek, seems also to be barely separable from the 

 Pleuromya (or Panopced) papyracea of Gabb, from the " Shasta Group " 

 of California. 



From the foregoing considerations the writer has long held the 

 opinion, first, that the whole of the Lower Shales at Cumshewa and 

 Skidegate Inlets belong to about the same geological horizon as the 

 Gault of England and Europe : and secondly, that there are now good 

 reasons for supposing that many of those rocks in the "Western Territo- 

 ries and California which have been hitherto regarded as Jurassic may 

 prove to be more nearly the equivalents of the earliest or oldest sub- 

 division of the Middle Cretaceous. 



4. " THE AGGLOMERATES, OB SUBDIVISION D." 



There is no palaeontological evidence which would afford any clue to 

 the probable age of the rocks of this subdivision. 



