﻿1861.] 



HECTOR ROCKY MOUNTAINS, ETC. 



411 



b. 20 feet of coarse and fine sandstone impregnated with lime, 

 also gravel and shingle, and bed of travertine (c) with di- 

 cotyledonous leaves. 

 Ancient valley- deposit ? — or underlying the Drift ? 



d. Present river-level with banks, 8 feet high, of silt and fine 

 sand, forming the " points " and densely wooded islands 

 in the channel. 



I was unable to determine whether these beds have been formed, 

 like the silt-banks of the river, at a time when it was much larger 

 than at present, or whether they are beds cropping out from beneath 

 the drift. They are quite consolidated, but this may have resulted 

 from the calcareous nature of the matrix. 



It will be seen that the observations I have made respecting the 

 distribution of the Tertiaries on the eastern plains are very disjointed 

 and unsatisfactory. As the Cretaceous strata overhanging the 

 Winnipeg group of lakes appear to dip to the west, again to rise to 

 the Coteau cles Prairies, it is probable that the trough which they 

 thus formed was occupied by Tertiaries of the same age as those that 

 cover the Cretaceous strata on the Upper Missouri ; but that, in the 

 immense denudation that has taken place, they have been unable to 

 withstand the erosion so well as the tough clays that underlie them, 

 which had therefore remained as a shoal further out to sea, while 

 along the shore the more yielding strata were being rapidly ground 

 down under the combined action of currents and stranded ice. 



Although it is probable that Tertiary basins occur in the plains 

 further west, especially some of the groups that yield lignite, these 

 will be afterwards described along with the Cretaceous strata, as 

 there is an absence of data by which to discriminate them. 



CRETACEOUS SYSTEM. 



Nearly the whole of the great area of prairie country from the 

 eastern axis to the Rocky Mountains is occupied by Cretaceous 

 strata, which have attained an enormous development throughout 

 the central portion of the North American continent. 



The classification of these strata, as they occur in the prairies to 

 the south, has been worked out during the last six years by Messrs. 

 Meek and Hayden with great success, and the results have been 

 published as memoirs in the ' Proceedings of the Academy of Natural 

 Sciences, Philadelphia.' The Reports of the various Pacific Railway 

 exploring expeditions also give details and descriptions of the fossil 

 remains which have been found in this group. 



Messrs. Meek and Hayden divide the Cretaceous System of the Upper 

 Missouri into five groups ; but my observations were not sufficiently 

 extended to warrant my referring the different Saskatchewan strata 

 to these without much doubt, more especially as I had not the 

 benefit of their valuable reports, which were published while I 

 was engaged in the exploration. In the following vertical section I 

 have therefore adopted a different method of lettering, only indi- 

 cating the probable equivalents of their section. In the case, how- 



