299 



CHAP. XXXIX. 



THE CARBONIFEROUS SERIES. JURASSIC FORMATION. 



Evidence of the Carboniferous Series. — ' Productus.' — Probability of the 

 Carboniferous Series being represented on the Flanks of the Riding 

 Mountain. — Occurrence in Nebraska Territory. — In Kansas Territory. — In 

 the North- West generally. — On the West Edge of the Fossiliferous Basin. 

 — Ammonites from the McKenzie River, probably from Jurassic Rocks. 

 — Ammonites Barnstoni. — Ammonites Billingsi. 



THE CARBONIFEROUS SERIES. 



The western limits of the Devonian Series are shown 

 on the map to follow the boundary of the Great Creta- 

 ceous table-land so well defined by Pembina Mountain, 

 Eiding Mountain, Duck Mountain, Porcupine Hill, the 

 Pas Mountain, and the high plateau similar to Pembina 

 Mountain which stretches from the Pas to the Main Sas- 

 katchewan, near and below Fort a la Corne. The country 

 at the base of this continuous boundary is uniformly hori- 

 zontal, and while Devonian rocks in position were seen 

 within thirty miles, and brine springs within ten miles of 

 Cretaceous shales on the precipitous flanks of the Eiding 

 Hill Eange, yet no evidence of any intermediate formation 

 was visible. 



During the ascent of the Eiding Mountain, a very 

 careful search was made for traces in the drift of the 

 higher series, in the hope of obtaining evidence of the 

 existence of Carboniferous rocks, but without success. 

 The boulders, so numerous on the ridges and the suc- 

 cessive terraces, were carefully examined, but they were 

 found to be derived altogether from the Laurentian Series, 



