
ROCKY MOUNTAINS—REVIEW OF SECTION. 71 
mountains again formed of blue limestone, along with a compact blue 
schist with red bands, giving a curious striped aspect to the rocks.” * 
154. Dr. Hector is not very clear as to the separation of the sup- 
posed Devonian and Carboniferous limestones, and they may indeed, very 
probably belong to a single series. Prof. Meek, in describing fossils from 
limestones occurring in the mountains south of the Boundary-line, which 
from the general facies, he believed to be Carboniferous ; mentions the 
fact that the forms, without exception, belong to genera, which are 
common both to that formation and the Devonian, and of which a small 
number are represented also in the Silurian. + 
155. Dr. Peale, in his report to Dr. Hayden { describes, at Spring 
Canon, Montana, about two hundred miles south of the Line, an interest- 
ing section which is clearly comparable with Series D, F, G, and H. It 
may be summarized as follows :— 
Cretaceous— 
Red, purple, and grey sandstones, with brown limestone.. 200 feet. 
Jurassic— 
Brown and yellowish limestones, with sandstones and thin 
quartaitesys. 312 isle.) le. MUA ai nea ds ae ca aacs AAG 
Triassic— 
Red and purple sandstones, sometimes calcareous, with 
one thin limestone near the top............2ceeeeee Gs" “ 
Carboniferous— 
Limestone, the upper layers arenaceous............e0+ VR. Ale 
Allowing for the distance by which the two regions are separated, the 
agreement is sufficiently close. We have first, a limestone comparable 
with D. The trap E. of the Boundary section, is probably intercalated 
among the beds here included in the Carboniferous, and separates the 
representatives of the lower compact limestone, from those of the upper 
flaggy and arenaceous beds ; which, in the Boundary section, are desig- 
nated Series F. Next, a great ascending series of limestones associated 
with reddish arenaceous beds. 
156. The beds classed-as Triassic, in the above section, are so-named 
merely from their analogy with those of that period in other regions. 
Dr. Hayden, elsewhere, states his belief, that the Triassic and Devonian 
series are wanting in Montana,§ and that below the lignite-bearing 
formation, follow in descending order, the Cretaceous, Jurassic, Carboni- 
ferous, and a great thickness of lower strata, probably Silurian, which 
rest unconformably on granitic and gneissic rocks. 
* Exploration of British North America., p. 239. 
+ U. 8. Geol. Surv. Territ., 1872., p. 432. t Ibid., p. 110. § Ibid., p. 28, 


