The Students Elements of Geology | Page 4

Sue Asscher [email protected]

THE STUDENT'S ELEMENTS OF GEOLOGY.
BY SIR CHARLES LYELL, BART., F.R.S.,
AUTHOR OF "THE PRINCIPLES OF GEOLOGY," "THE
ANTIQUITY OF MAN," ETC.
(FIGURE A. FROM BOTTOM TO TOP: PRIMARY OR
PALEOZOIC. Bronteus flabellifer. SECONDARY OR MESOZOIC.
Ammonites rhotomagensis. TERTIARY OR CAINOZOIC.
Nummulites laevigata.)
(FIGURE B. Thecosmilia annularis.)

WITH MORE THAN 600 ILLUSTRATIONS ON WOOD.

PREFACE.
The LAST or sixth EDITION of my "Elements of Geology" was
already out of print before the end of 1868, in which year I brought out
the tenth edition of my "Principles of Geology."
In writing the last-mentioned work I had been called upon to pass in
review almost all the leading points of speculation and controversy to
which the rapid advance of the science had given rise, and when I
proposed to bring out a new edition of the "Elements" I was strongly
urged by my friends not to repeat these theoretical discussions, but to
confine myself in the new treatise to those parts of the "Elements"
which were most indispensable to a beginner. This was to revert, to a
certain extent, to the original plan of the first edition; but I found, after
omitting a great number of subjects, that the necessity of bringing up to
the day those which remained, and adverting, however briefly, to new
discoveries, made it most difficult to confine the proposed abridgment
within moderate limits. Some chapters had to be entirely recast, some
additional illustrations to be introduced, and figures of some organic
remains to be replaced by new ones from specimens more perfect than
those which had been at my command on former occasions. By these
changes the work assumed a form so different from the sixth edition of
the "Elements," that I resolved to give it a new title and call it the
"Student's Elements of Geology."
In executing this task I have found it very difficult to meet the
requirements of those who are entirely ignorant of the science. It is only
the adept who has already overcome the first steps as an observer, and
is familiar with many of the technical terms, who can profit by a brief
and concise manual. Beginners wish for a short and cheap book in
which they may find a full explanation of the leading facts and
principles of Geology. Their wants, I fear, somewhat resemble those of
the old woman in New England, who asked a bookseller to supply her
with "the cheapest Bible in the largest possible print."

But notwithstanding the difficulty of reconciling brevity with the
copiousness of illustration demanded by those who have not yet
mastered the rudiments of the science, I have endeavoured to abridge
the work in the manner above hinted at, so as to place it within the
reach of many to whom it was before inaccessible.
CHARLES LYELL.
73 Harley Street, London, December, 1870.
CONTENTS.



CHAPTER I.
ON THE DIFFERENT CLASSES OF ROCKS.
Geology defined. Successive Formation of the Earth's Crust.
Classification of Rocks according to their Origin and Age. Aqueous
Rocks. Their Stratification and imbedded Fossils. Volcanic Rocks, with
and without Cones and Craters. Plutonic Rocks, and their Relation to
the Volcanic. Metamorphic Rocks, and their probable Origin. The term
Primitive, why erroneously applied to the Crystalline Formations.
Leading Division of the Work.



CHAPTER II.

AQUEOUS ROCKS-- THEIR COMPOSITION AND FORMS OF
STRATIFICATION.
Mineral Composition of Strata. Siliceous Rocks. Argillaceous.
Calcareous. Gypsum. Forms of Stratification. Original Horizontality.
Thinning out. Diagonal Arrangement. Ripple-mark.



CHAPTER III.
ARRANGEMENT OF FOSSILS IN STRATA-- FRESH-WATER
AND MARINE.
Successive Deposition indicated by Fossils. Limestones formed of
Corals and Shells. Proofs of gradual Increase of Strata derived from
Fossils. Serpula attached to Spatangus. Wood bored by Teredina.
Tripoli formed of Infusoria. Chalk derived principally from Organic
Bodies. Distinction of Fresh-water from Marine Formations. Genera of
Fresh-water and Land Shells. Rules for recognising Marine Testacea.
Gyrogonite and Chara. Fresh-water Fishes. Alternation of Marine and
Fresh-water Deposits. Lym-Fiord.



CHAPTER IV.
CONSOLIDATION OF STRATA AND PETRIFACTION OF
FOSSILS.

Chemical and Mechanical Deposits. Cementing together of Particles.
Hardening by Exposure to Air. Concretionary Nodules. Consolidating
Effects of Pressure. Mineralization of Organic Remains. Impressions
and Casts: how formed. Fossil Wood. Goppert's Experiments.
Precipitation of Stony Matter most rapid where Putrefaction is going on.
Sources of Lime and Silex in Solution.



CHAPTER V.
ELEVATION OF STRATA ABOVE THE SEA.-- HORIZONTAL
AND INCLINED STRATIFICATION.
Why the Position of Marine Strata, above the Level of the Sea, should
be referred to the rising up of the Land, not to the going down of the
Sea. Strata of Deep-sea and Shallow-water Origin alternate. Also
Marine and Fresh-water Beds and old Land Surfaces. Vertical, inclined,
and folded Strata. Anticlinal and Synclinal Curves. Theories to explain
Lateral Movements. Creeps in Coal-mines. Dip