adapted to a limited region only, will be found to present a fair
synopsis of geological history. There is perhaps even some advan-
tage, as regards definiteness and precision, in tracing the growth of
a single typical area, especially one so admirably adapted to the
purpose as our own, rather than attempting a sketch of universal or
even continental geology, since at present our knowledge of large
portions of these wider fields is too incomplete to admit of a
detailed tracing of the stages of growth, and too complicated to be
easily described and readily conceived.
In the execution of the plan, regard has been had to the conven-
ience of the general reader, as well as to the class-room student.
The latter will possibly miss the customary artificial form of a text-
book, but it is hoped he will not regret it. It is possible to destroy
the vitality of a subject by dismembering it, and reducing it to
formal definitions. Worse than this, it is possible to convey an arti-
ficial and even a false impression of the subject, rather than the
true and natural one, by enforced system and rigid formalism in its
presentation.
In the endeavor to make the current of thought clear, the attempt
has been, not so much to shallow the stream, as to clarify the
waters; with what success, the reader must judge.
Those portions of the subject which relate to the origin and pecul-
iarities of the geographical features of the State, are commended
to teachers as furnishing subject-matter for oral instruction auxiliary
to the text-book study of State geography.
Part II is intended as a measurable contribution to studies in
Natural History, in the broad sense of that term, embracing miner-
als and rocks, as well as plants and animals. The catalogues will
serve as convenient check and reference lists for students and col-
lectors, while they represent, in greater or less fullness, the ampli-
tude of Wisconsin's native productions. It is not presumed that
any of the lists are entirely complete. It is quite impossible to
make them so at once. But an almost necessary step in that direc-
tion is the publication and wide distribution of such catalogues,
which may serve as bases for additions by numerous local observers
and collectors, by whose aid some approach to completeness may, in
time, be secured.
The preparation of such lists, being an incidental, rather than a
specific, function of the Survey, has been largely the gratuitous con-
tribution of the authors, and merits a hearty recognition of their
generosity. Beside the value of the lists as such, the descriptions
and economic suggestions and discussions which accompany them,


VI


PREFACE.