HELL CREEK FORMATION 



359 



INVERTEBBATES 



XJnio cesopiformis Whitf. 



" cordiculoides WMtf. 



" pyramidellus WMtf. 



" verrucosiformis Whitf. 



" retusoides Whitf. 



" hrowni Whitf. 



" percorrugata Whitf. 



" postMplicata Whitf. 



" aldrichi White 



" dance White 



" holmesiana White 



" vetusta Meek 



" cryptorhynchus White 



" Masopoides Whitf. 



Unio cylindricoides Whitf. 



" letsoni Whitf. 



" gihhosoides Whitf. 



" pyramidatoides Whitf. 



" suhtrigonalis Whitf. 

 Sphwrium planum M. and H. 

 CorMcula suhelUptica M. and H. 

 Campeloma multoUneata M. and H. 

 " vetula M. and H. 



" producta White 



Vivipara pUcapressa White 

 Cassiopella turricula White 

 Thaumastus Ummceiformis White 

 Bulinus rhomboideus M. and H. 



Equisetum Iwvigatum 

 Rhamnus salicifoUus 



FLOBA 



Ficus spectaMUs 

 Sequoia heerii? 



Eed Deer Eiver, Alberta, Canada 



This river presents one of the finest sections for the study of Mesozoie 

 and Eocene rocks to be seen on the continent. In a distance of approxi- 

 mately 300 miles, starting from the town of Eed Deer, it cuts through 

 and into sediments of four distinct formations, Paskapoo, Edmonton, 

 Pierre, Belly Eiver, well defined by the character of sedimentation and 

 fossil remains. 



The latest determination of these formations by the Canadian Geo- 

 logical Survey, 1913, is as follows: 



Paskapoo 



Edmonton 



Fort Pierre 

 Belly River 

 Fort Pierre 



Laramie 



Cretaceous 



Tertiary 



Mesozoie 



The term Laramie is used by the Canadian Survey with the implied 

 meaning given by G. M. Dawson in the "Eeport of Progress" for 1880- 

 '81-^82, page 4B, as a group term to include all the stratigraphically con- 

 formable formations from the top of the Pierre-Fox Hill to the uncon- 

 formity below the Oligocene. 



The river canyon averages about a mile in width at the prairie level 

 and ranges from 200 to 500 feet in depth, presenting for the most part 



