1877.] Catastrophism and Evolution. 455 
able fully to survey, but its great features, the lofty chains of the 
mountains which made its bones,,were very nearly coextensive 
with our existing systems, the Appalachians and Cordilleras. 
The caiion-cutting rivers of the present Western mountains have 
dug out the peaks and flanks of those underlying, primeval up- 
lifts and developed an astonishing topography : peaks rising in a 
single sweep thirty thousand feet from their bases, precipices 
lifting bold, solid fronts ten thousand feet into the air, and pro- 
found mountain valleys. The work of erosion which has been 
carried on by torrents of the Quaternary age — that is to say, 
within the human period — brings to light buried primeval 
chains far loftier than any of the present heights of the globe. 
Man’s enthusiastic hand may clear away the shallow dust or rub- 
bish from an Oriental city, and lay bare the stratified graves of 
perished communities: it is only a mountain torrent which can 
dig through thousands of feet of solid rock and let in the light of 
day on the time-stained features of a long-buried continent. 
-~ Archzean America was made up of what was originally ocean 
beds lifted into the air and locally crumpled into vast mountain 
chains, which were eroded by torrents into true subaerial mount- 
ain peaks. This conversion of sea strata into the early conti- 
nent is the first record of a series of oscillations in which land 
and sea successively occupied the area of America. In pre-Cam- 
brian time the continent we are considering sank, leaving some 
of its mountain tops as islands, and the neighboring oceans flowed 
over it, their bottoms emerging and becoming continents. This 
is the second of the recorded oscillations of the first magnitude. 
After Archæ-America had began to sink and its bounding 
land masses to emerge, the conditions on the two ‘sides of the 
ocean began to show characteristic difference of behavior, — dif- 
ference in the rate of subsidence, — that very difference of rate 
which uniformitarianism denies. 
Palx-Pacifis and Palw-Atlantis were land areas which I con- 
ceive to be of continental magnitude, from the vast volumes of 
sediment brought down by their rivers and poured into the 
Palew-American Ocean. American geologists have found the rec- 
ord along the eastern margin of that ocean, namely, the present 
Appalachian region, so legible that they are agreed as to its main 
features. There is no plea of illegibility here. The total sedi- 
ment which fringed the shore of Palw-Atlantis was about forty- 
five thousand feet in maximum, but the original ocean, when 
Strata began to gather, was not forty-five thousand feet deep. 
