1877.] Catastrophism and Evolution. 461 
gorges were altogether carved out since the beginning of the 
glacial period ; thirdly, the modern rivers, mere echoes of their 
parent streams of the early Quaternary age. As between these 
three, the early Quaternary rivers stand out vastly the most 
powerful and extensive. The present rivers are utterly incapa- 
ble, with infinite time, to perform the work of glacial torrents. 
So, too, the Pliocene streams, although of very great volume, 
were powerless to wear their way down into solid rock thousands 
of feet, at the rapid rate of the early Quaternary floods. Be- 
tween these three systems of rivers is all the difference which 
separates a modern (uniformitarian) stream and a terrible catas- 
trophic engine, the expression of a climate in which struggle for 
existence must have been something absolutely inconceivable 
when considered from the water precipitations, floods, torrents, 
and erosions of to-day. 
Uniformitarians are fond of saying that give our present rivers 
time, plenty of time, and they can perform the feats of the past. 
It is mere nonsense in the case of the cafions of the Cordilleras. 
They could never have been carved by the pigmy rivers of this 
climate to the end of infinite time. And, as if the sections and 
profiles ‘of the caiions were not enough to convince the most skep- 
tical student, there are left hundreds of dry river-beds, within 
whose broad valleys, flanked by old steep banks and eloquent 
with proofs of once-powerful streams, there is not water enough 
to quench the thirst even of a uniformitarian. Those extinct 
rivers, dead from drought, in connection with the great cañon sys- 
tem, present perfectly overwhelming evidence that the general de- 
position of aerial water, the consequent floods and torrents, form- 
ing as they all do the distinct expression of asharply-defined cycle 
of climate, as compared either with the water phenomena of the 
immediately preceding Pliocene age or with our own succeeding 
condition, constitute an age of water catastrophe whose destruc- 
tive power we only now begin distantly to suspect. 
I have given you what in my belief are sound geological con- 
clusions, the want of time alone causing me to waive the slow 
production of proofs. I believe I am fully prepared to sustain 
e assertions, first, that the rate of physical change progressing 
to-day in all departments of terrestrial action is inadequate to 
produce the grander features of American geological. history ; 
secondly, that in the past, at intervals, the dynamic rate has been 
so sharply accelerated as to bring about exceptional results ; 
thirdly, that these results have been catastrophic in their effect 
