



Produced by Thomas Cosmas. Produced from files made
available on The Internet Archive and a physical copy of
the book.









THE

ELEMENTS OF GEOLOGY;

ADAPTED TO THE USE OF

SCHOOLS AND COLLEGES.


BY

JUSTIN R. LOOMIS,

PROFESSOR OF CHEMISTRY AND GEOLOGY IN WATERVILLE COLLEGE.


WITH NUMEROUS ILLUSTRATIONS.


BOSTON:

GOULD AND LINCOLN,

59 WASHINGTON STREET.

1852


Entered according to Act of Congress, in the year 1852,

By GOULD & LINCOLN,

In the Clerk's Office of the District Court of the District of
Massachusetts.


Stereotyped by

HOBART & ROBBINS,

BOSTON.

PRESS OF G. C. RAND, CORNHILL, BOSTON.




PREFACE


In preparing the following work, it was intended to present a systematic
and somewhat complete statement of the principles of Geology, within
such limits that they may be thoroughly studied in the time usually
allotted to this science.

A sufficient number of leading facts has been introduced to enable the
learner to feel that every important principle is a conclusion to which
he has himself arrived; and yet, for the purpose of compression, that
fullness of detail has been avoided with which more extended works
abound. In furtherance of the same object, authorities are seldom cited.

The consideration of geological changes is made a distinct chapter,
subsequent to the one on the arrangement of materials. It should,
however, be remembered that these processes of arranging and disturbing
are not thus separated in time. In nature the two processes are always
going on together.

It seemed important to exhibit the science with as much unity and
completeness as possible; and hence, discussions upon debatable points
in Theoretical Geology, so interesting to mature geologists, would have
been out of place here; and yet those more intricate subjects have not
been omitted. A large proportion of the work is devoted to the
explanation of geological phenomena, in order to convey an idea of the
modes of investigation adopted, and the kind of evidence relied on.
Where diversities of opinion exist, that view has been selected which
seemed most in harmony with the facts; and the connection has not often
been interrupted to combat, or even to state, the antagonist view.

Technical terms have, in a few instances, been introduced, and
principles referred to, which are subsequently explained. The index
will, however, enable the student to understand them, without a separate
glossary.

Some may prefer to commence with the second chapter, deferring the study
of the elementary substances, minerals and rocks, to the last. Such a
course may be pursued without special inconvenience.

Questions have been added, for the convenience of those teachers who may
prefer to conduct their recitations by this means. But, when the
circumstances of the case admit of it, a much more complete knowledge of
the subject will be acquired by pupils who are required to analyze the
sections, and proceed with the recitation themselves; while the teacher
has only to correct misapprehension, explain what may seem obscure, and
introduce additional illustrations.




LIST OF ILLUSTRATIONS.


   1. Columnar Trap, New Holland. (_Dana._)

   2. The four divisions of rocks, and their relative positions. _A_,
        Volcanic Rocks. _B_, Granite. 1, 2, 3, 4, Granite of different
        ages. _C_, Metamorphic Rocks. _D_, Fossiliferous Rocks.
        (_Lyell._)

   3. Granite veins in slate, Cape of Good Hope. (_Hall._)

   4. Granite veins traversing granite. (_Hitchcock._)

   5. Extinct volcanoes of Auvergne. (_Scrope._)

   6. Lava of different ages, Auvergne. (_Lyell._)

   7. Strata folded and compressed by upheaval of granite.

   8. Favosites Gothlandica.

   9. Catenipora escharoides. (Chain coral.)

  10. Caryocrinus ornatus. (_Hall._)

      { Leptaena alternate. Orthis testudinaria.  }
  11. {                                          }(_Hall._)
      { Delthyris Niagarensis.                   }

  12. Section of a chambered shell, showing the chambers and the
        siphuncle.

  13. Orthoceras.

  14. Curved Cephalopoda, _a_, Ammonite; _b_, Crioceras; _c_,
        Scaphite; _d_, Ancyloceras; _e_, Hamite; _f_, Baculite;
        _g_, Turrilite. (_Agassiz and Gould._)

  15. Trilobite.

  16. Cephalaspis Lyellii. (_Agassiz._)

  17. Pterichthys oblongus. (_Ag