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ried into tlie lake, and scattered over its silent depths. Autumn 
and winter followed, and sent down their floods, swollen with 
the rain, and carrying along the debris of the mountains around. 
While the gravel and sand brought down by the streams 
were deposited at the sides of the lakes, the lighter particles of 
floating mud were spread over its entire extent, and settled down 
in the stillness of its deeps. The cypris scales were the de- 
posits of the summer floods; the alternating marl was the 
product of the winter's rain. Every layer, therefore, may be 
regarded as the record of a year ; and if these layers are as 
“ thin as paper," in masses “ several hundred feet thick," a 
very extended time must have elapsed before the lake had 
its peaceful repose disturbed. If we reckon ten of these divi- 
sions to an inch— -and the description would lead us to suppose 
that there are many more — stratified masses thus formed, and 
of the thickness Sir Charles mentions, must indicate a period 
of at least some fifty thousand years. These marls, moreover, are 
spoken of as representing only the latter part of the period, 
during which the Upper Eocene was formed ; and the whole 
of that epoch seems to have been brief when compared to the 
duration of others. 
Who then can calculate the age of the earth, or reckon up 
the years of its many generations ! 
Uniformity of System in the Course of Creation. 
We now proceed to remark that the history, written in the 
records of the rocks, very plainly shows that in all the periods 
of the earth's existence, the laws that regulate the material 
world have been the same as those that are now in operation. 
The ripple-mark left by the tiny billow on the muddy shore, and 
the impression made by the raindrop on the yielding sand, can 
still be traced in formations many epochs old. The annual 
rings that we find in the trunks of fossil trees testify to the 
regular return of “ summer and winter, seed-time and har- 
vest," in ages long since gone by. 
Leaving it to others to speculate on the law of progression, 
according to which animals of higher development and more 
delicate organization have, from time to time, been introduced 
into the terrestrial sphere, we content ourselves with remarking 
that in all the various stages through which the world has 
passed, we find creatures formed with an organization that 
was admirably fitted for the circumstances in which they were 
placed. When the globe was subject to volcanic convulsions, 
far more terrible than any we now experience, and the ocean 
was tossed with tempests of proportionate violence, the ani- 
