do not know from what you do know already.

Now, I ask of you to employ the same common sense when you read and
think of Geology.

It is very necessary to do so. For in past times men have tried to
explain the making of the world around them, its oceans, rivers,
mountains, and continents, by I know not what of fancied cataclysms
and convulsions of nature; explaining the unknown by the still more
unknown, till some of their geological theories were no more
rational, because no more founded on known facts, than that of the
New Zealand Maories, who hold that some god, when fishing, fished up
their islands out of the bottom of the ocean. But a sounder and
wiser school of geologists now reigns; the father of whom, in England
at least, is the venerable Sir Charles Lyell. He was almost the
first of Englishmen who taught us to see--what common sense tells us-
-that the laws which we see at work around us now have been most
probably at work since the creation of the world; and that whatever
changes may seem to have taken place in past ages, and in ancient
rocks, should be explained, if possible, by the changes which are
taking place now in the most recent deposits--in the soil of the
field.

And in the last forty years--since that great and sound idea has
become rooted in the minds of students, and especially of English
students, geology has thriven and developed, perhaps more than any
other science; and has led men on to discoveries far more really
astonishing and awful than all fancied convulsions and cataclysms.

I have planned this series of papers, therefore, on Sir Charles
Lyell's method. I have begun by trying to teach a little about the
part of the earth's crust which lies nearest us, which we see most
often; namely, the soil; intending, if my readers do me the honour to
read the papers which follow, to lead them downward, as it were, into
the earth; deeper and deeper in each paper, to rocks and minerals
which are probably less known to them than the soil in the fields.
Thus you will find I shall lead you, or try to lead you on,
throughout the series, from the known to the unknown, and show you
how to explain the latter by the former. Sir Charles Lyell has, I
see, in the new edition of his "Student's Elements of Geology," begun
his book with the uppermost, that is, newest, strata, or layers; and
has gone regularly downwards in the course of the book to the lowest
or earliest s