as Time-boundaries in Geological History. 231 
of the Permian period. Murchison remarks, concerning the 
epoch following the Carboniferous, that it was then “that the 
coal-strata and their antecedent formations were very generally 
broken up, and thrown by grand upheavals into separate basins, 
which were fractured by numberless powerful dislocations.” The 
formation of the main part of the Ural chain—the mountains 
on the eastern border of Europe (dividing the Orient into its 
eastern and western portion)—has been referred to this time. 
Again, the epoch of the elevation of the Rocky Mountains 
was similarly eminent in Kuropean history. From the Triassic 
onward to the middle or later Cretaceous, there had been in Eu- 
rope only oscillations of level, and relatively small uplifts or dis- 
turbances. The elevation of the range of the Céte d’Or and 
Cévennes in France, and of the Erzgebirge in Saxony, all north- 
Orient (for these mountains belong to the border-region of the 
Orient just as the Rocky Mountains do to that of the Occident, 
continued to the middle or later Eocene. But the transition in 
kinds of life which accompanied the transition in time from the 
was, in fact, the prominent epoch of physical change over the 
globe, notwithstanding the changes of level which subsequently 
during the Carboniferous age, and probably occupied in their 
ariot Rock 
menced their grand movements upward as the egg age was 
e Tertiary. 
ere are thus two specially prominent periods of mountain- 
