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they sank again, received another pile of sediment, were consoli- 
dated, faulted, and upheaved as before. Then came the formation 
of another plain of marine denudation, shaped at this point out of 
the Red Rocks, which formerly extended over here. Yet again 
they went down, to be once more enveloped in newer deposits. 
Lastly, they were upheaved again, for the last time, in the 
Miocene period ; the rocks were exposed for a period that we are 
unable to form any conception of, and again denuded still further, 
so that the two prior-formed plains of marine denudation were re- 
exposed. Then, out of the rock composing these two older plains, 
subaerial denudation has since been unceasingly at work carving 
hiil and dale, escarpment and dip slope, out of the old marine 
surface. And, afterwards, came the ice of the great Glacial Period to 
smooth and round and impart flowing contours to the irregularities 
of the surface produced by weathering. And, last thing of all, 
comes in subaerial denudation again to replace the smooth contours 
and sweeping curves imparted by the ice with its own evidence of 
that waste and destruction which all we know of geology tells us 
has been going on from the remotest periods of the past, and which, 
we may feel sure, will go on until the very end of time. 
