THEIR DEPOSITS AND DRAINAGE. 659 
genera now living on the earth's surface, with many strange 
forms long since extinct— formed the prey of carnivores 
commensurate to these in power and numbers. The coo of 
the dove and the whistle of the quail were answered by the 
scream of the eagle; and the lowing of herds and the bleat- 
ing of flocks come to the ear of the imagination, mingled 
with the roar of the lion, the howl of the wolf, and the des- 
pairing cry of the victim. Yielding to the slow-acting but 
irresistible forces of nature, each in succession of thesi va- 
rious animal forms has disappeared till all have passed away 
or been changed to their modern representatives, while the 
country they inhabited, by the upheaval of its mountains, 
the deepening of its valleys, the filling and draining of its 
great lakes, has become what it is. 
These changes which I have reviewed in an hour seem like 
the swiftly consecutive pietures of the phantasmagoria or the 
shifting scenes of the drama, but the eons of time in which 
they were effected are simply infinite and incomprehensible 
to us. We have no reason to suppose that ferra firma was 
less firm, or that the order of nature, in which no change is 
recorded within the historie period, was less constant then 
than now. At the present rate of change— throwing out 
man's influence —a period infinite to us would be required 
to revolutionize the climate, flora and fauna, and there is no 
evidence that changes were more rapid during the Tertiary 
ages, 
Every day sees something taken from the rocky barrier of 
Niagara ; and, geologically ipeaking; at no remote time our 
great lakes will have shared the fate of those that once ex- 
isted at the far West. Already they have been reduced to 
less than half their former area—and the water level has 
been depressed three hundred feet or more. This process is 
likely to go on until they are completely emptied. 
The cities that now stand upon their banks will, ere that 
time, have grown colossal in size, then gray with age, then 
have fallen into’ decadence and their sites be long forgotten, 
