CHAPTER VI. 
General Views. — Circumstances attending the Deposition of the Moun- 
tain Limestone Formation. 
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X he most exact details in natural science are valuable not so much 
for their own sake as for the solid foundation they afford for the estab- 
lishment of laws of phenomena, the explanation of which is the province 
of theory. The search for theory, the noblest exercise of cultivated 
minds employed in the works of nature, would never have fallen under 
suspicion and prejudice, had it been conducted according to the only 
possible method likely to yield success. To discountenance speculations 
which trench on the province of observation and inference, especially 
in a science of such complicated relations as geology, is not only wise 
but necessary; but when vast multitudes of facts are gathered,— the 
only materials for a theory collected,— it is equally wise and necessary 
to employ on geological phenomena the processes of reasoning to which 
we are indebted for the laws of the phenomena of chemistry, and the 
combination of such laws in a general theory of astronomy. 
For many and obvious reasons it is desirable that the task of com- 
bining local truths (the first order of inferences in geology) should be 
attempted by the same person who has ascertained them. To him 
gradations and variations are often known too minute for description 
yet necessary to the train of argument, and influencing rightly his own 
conviction ; the relative value of the observations has due weight with 
him in clearing up discrepancies and correcting results ; and thus data 
are made available which would be too incomplete or apparently dis- 
agreeing for other men to employ with safety. Besides it happens in 
geology as in other sciences, that few persons but the observer will be 
