



Produced by Charlene Taylor, Tom Cosmas and the Online
Distributed Proofreading Team at http://www.pgdp.net (This
file was produced from images generously made available
by The Internet Archive/American Libraries.)









Transcriber's Note

Text emphasis is displayed as _Italics_ and =Bold= respectively.
Superscript characters are denoted with the carat character (i.e., 8^e).
Whole and fractional parts are displayed as 5-1/2.




                               FRAGMENTS

                                  OF

                              EARTH LORE


                [Illustration: PLATE I

                           OROGRAPHIC MAP OF

                               SCOTLAND]




                               FRAGMENTS

                                  OF

                              EARTH LORE


                         SKETCHES & ADDRESSES

                      Geological and Geographical

                                  BY

               JAMES GEIKIE, D.C.L., LL.D., F.R.S., &c.


         MURCHISON-PROFESSOR OF GEOLOGY AND MINERALOGY IN THE
                        UNIVERSITY OF EDINBURGH
            FORMERLY OF H.M. GEOLOGICAL SURVEY OF SCOTLAND

                      WITH MAPS AND ILLUSTRATIONS

                               EDINBURGH
                        JOHN BARTHOLOMEW & CO.
         LONDON: SIMPKIN, MARSHALL, HAMILTON, KENT & Co., Ltd.
                                 1893




PREFACE.


The articles in this volume deal chiefly with the history of Glacial
times and the origin of surface-features. As they were not written with
any view to their subsequent appearance in a collected form, each is so
far independent and complete in itself. Under these circumstances some
repetition was unavoidable, if the articles were not to be recast, and
I did not think it advisable to make such radical alteration. With the
exception of verbal changes and some excisions, therefore, the papers
remain substantially in their original state. Here and there a footnote
has been added to indicate where the views expressed in the text have
since been modified; but I have not been careful to insert such notes
throughout. Geologists, like other folk, live and learn, and the reader
will probably discover that the opinions set forth in some of the
later articles are occasionally in advance of those maintained in the
writer's earlier days.

I have to thank the Publishers of _Good Words_ for allowing me to
republish the articles on the Cheviot Hills and the Outer Hebrides. My
acknowledgments are also due to Mr. Bartholomew for the excellent maps
with which the volume is so well illustrated.

  Edinburgh, _April 5th, 1893_.




LIST OF MAPS.


  Plate   I. PHYSICAL FEATURES OF SCOTLAND      _Frontispiece_

    "    II. STRUCTURE OF MOUNTAINS                         60

    "   III. PAST AND PRESENT GLACIATION OF THE WORLD      193

    "    IV. ICE AGE IN NORTHERN EUROPE                    324

    "     V. THE GEOGRAPHICAL EVOLUTION OF CONTINENTS      348

    "    VI. BATHY-HYPSOMETRICAL MAP, ILLUSTRATING
              DEVELOPMENT OF COAST-LINES                   428




CONTENTS.


  CHAP.                                                 PAGE

     I. GEOGRAPHY AND GEOLOGY                              1

    II. THE PHYSICAL FEATURES OF SCOTLAND                 14

   III. MOUNTAINS: THEIR ORIGIN, GROWTH, AND DECAY        36

    IV. THE CHEVIOT HILLS                                 62

     V. THE LONG ISLAND, OR OUTER HEBRIDES               125

    VI. THE ICE AGE IN EUROPE AND NORTH AMERICA          160

   VII. THE INTERCROSSING OF ERRATICS IN GLACIAL
          DEPOSITS                                       194

  VIII. RECENT RESEARCHES IN THE GLACIAL GEOLOGY
          OF THE CONTINENT                               220

    IX. THE GLACIAL PERIOD AND THE EARTH-MOVEMENT
          HYPOTHESIS                                     248

     X. THE GLACIAL SUCCESSION IN EUROPE                 288

    XI. THE GEOGRAPHICAL EVOLUTION OF EUROPE             326

   XII. THE EVOLUTION OF CLIMATE                         349

  XIII. THE SCIENTIFIC RESULTS OF DR. NANSSEN'S
          EXPEDITION                                     382

   XIV. THE GEOGRAPHICAL DEVELOPMENT OF COAST-LINES      393




I.

Geography and Geology.[A]

[A] Portion of a lecture given in 1886 to the Class of Geology in the
University of Edinburgh.


The teaching of Geography naturally occupies a prominent place in
every school curriculum. It is rightly considered essential that we
should from an early age begin to know something of our own and other
countries. I am not sure, however, that Geography is always taught in
the most interesting and effective manner. Indeed, according to some
geographers, who are well qualified to express an opinion, the manner
in which their subject is presented in many of our schools leaves much
to be desired. But a decided advance has been made in recent years,
and with the multiplication of excellent text-books, maps, and other
appliances, I have no doubt that this improvement will continue. When
I attended school the text-books used by my teachers were about as
repellent as they could be. Our most important lesson was to commit to
memory a multitude of place-names, and the maps which were supposed
to illustrate the text-books were, if possible, less interesting and
instructive. Nowadays, however, teachers have a number of more or less
excellent manuals at their service, and the educational maps issued by
our cartographers show in many cases a very great advance on the bald
and misleading caricatures which did duty in my young days as pictures
of the earth's surface.

During the progress of some war we often remark that the task of
following the military operations compels us to brush up our Geography.
I am uncharitable enough to suspect that it would frequently be
truer to say that, before these campaigns commenced, we had no such
knowledge to brush up. The countries involved in the commotion were
probably mere names to many of us. We had no immediate interest in
them or their inhabitants, and had we been asked, before the outbreak
of hostilities, to indicate the precise positions of the places upon a
map, some of us perhaps might have been sorely puzzled to do so. Nor
is such ignorance always discreditable. One cannot know everything;
the land-surface of the globe contains upwards of 50 millions of
square miles, and one may surely be excused for not having a detailed
knowledge of this vast area. I have referred to the subject simply
because I think it gives us a hint as to how the teaching of Political
Geography might be made most instructive and interesting. Historical
narrative might often be interwoven with the subject in such a way
as to fix geographical features indelibly on the memory. Striking
and picturesque incidents, eventful wars, the rise and progress of
particular trades, the routes followed by commerce, the immigration
and emigration of races, the gradual development of the existing
political divisions of the Old World, the story of Columbus and the
early voyagers, the geographical discoveries of later times--all these,
and such as these, might be introduced into our lessons in Political
Geography. The wanderings of a Mungo Park, a Bruce, a Livingstone, a
Stanley, traced on a good map, could not fail to arrest the attention
of the youthful student of African geography. In like manner, the
campaigns of the great Napoleon might be made to do good service
in illustrating the geographical features of large portions of our
own continent. Then, as regards Britain, what a world of poetry and
romantic story clings to every portion of its surface--why, the very
place-names themselves might suggest to any intelligent teacher themes
and incidents, the deft treatment of which would make the acquisition
of Geography a delightful task to the dullest boy or girl.

The intimate relation that obtains between Political Geography and
History has indeed long been recognised, and is in fact self-evident.
And we are all well aware that in our school manuals of Geography it
has been usual for very many years to note the scenes of remarkable
events. Such notes, however, are of necessity extremely brief; and it
need hardly be said that to fully incorporate history in a text-book of
general Geography would be quite impracticable. It might be done to a
certain extent for our own and a few of the more important countries;
but similar detail need not be attempted in regard to regions which are
of less consequence from the political point of view. Indeed, I should
be inclined to leave the proper application of historical knowledge in
the teaching of Geography very much to the teacher himself, who would
naturally select such themes and incidents as seemed best adapted to
attract the attention of his pupils. Be that, however, as it may,
it is enough for my present purpose if I insist upon the fact that
the proper study of Political Geography involves the acquisition of
some historical knowledge. One can hardly conceive the possibility
of an intelligent student taking pains to become acquainted with the
political geography of a country without at the same time endeavouring
to learn something of its history--otherwise, his geographical
attainments would hardly surpass those of a commercial traveller, whose
geographical studies have been confined to the maps and tables of his
Bradshaw.

But if it be impossible to ignore History in the teaching of Political
Geography, it is just as impossible to exclude from our attention
great physical features and characteristics. Surface-configuration,
climate, and natural products all claim our attention. It is obvious,
in fact, that the proper study of Political Geography must give us
at least a general notion of the configuration, the river-systems,
and climatic conditions of many different lands. For has not the
political development of races depended most largely on the physical
conditions and natural resources of the countries occupied by them?
So far, then, as these have sensibly influenced the progress of
peoples, they come naturally under the consideration of Political
Geography. Thus, if Political Geography be closely connected and
interwoven, as it were, with History, not less intimate are its
relations to Physical Geography. It does not embrace all Physical
Geography, but it introduces us to many facts and phenomena, the
causes and mutual relations of which we cannot understand without
first mastering the teachings of Physical Geography. In the study of
this latter science we come more closely into contact with Nature;
we cease to think of the surface of the earth as parcelled out into
so many lots by its human occupants--we no longer contemplate that
surface from the limited point of view of the political geographer--we
are now not merely members of one particular community, but have
become true citizens of the world. To us north and south, east and
west are of equal interest and importance. Our desire now is to
understand, if haply we may, the complex system of which we ourselves
form a part. The distribution of land and water--the configuration of
continental areas and oceanic basins--the circulation of oceanic and
terrestrial waters--earth-movements and volcanoes--ice-formations--the
atmosphere--climatology--the geographical distribution of plants
and animals--in a word, _the world as one organic whole_ now forms
the subject of our contemplation. Such being the scope of Physical
Geography, it is satisfactory to know that its importance as a subject
of study in our schools has been fully recognised. This being admitted,
I shall now proceed to show that Physical Geography, although, like
Political Geography, it is a separate and distinct subject, yet, just
as the study of the latter involves some knowledge of History, so
the prosecution of Physical Geography compels us to make a certain
acquaintance with Geology. We cannot, in fact, learn much about the
atmosphere, about rain and rivers, glaciers and icebergs, earthquakes
and volcanoes, and the causes of climate, without at the same time
becoming more or less familiar with the groundwork on which geological
investigations are based. And just as a knowledge of history enables
us better to understand the facts of Political Geography, so some
acquaintance with the results of geological inquiry are necessary
before we can hope to comprehend many of the phenomena of which
Physical Geography treats. Let me try to make this plain. The physical
geographer, we shall suppose, is considering the subject of terrestrial
waters. He tells us what is meant by the drainage-system of a country,
points out how the various minor water-courses or brooks and streams
unite to form a river, describes for us the shape of the valley through
which a typical river makes its way--how the valley-<DW72> diminishes
from the mountains onwards to the sea-coast--how, at first, in its
upper or mountain-track, the flow of the river is torrential--how,
as the <DW72> of the valley decreases, the river begins to wind about
more freely, until it reaches the head of its plain-track or delta,
when, no longer receiving affluents, it begins to divide, and enters
the sea at last by many mouths. He tells us further what proportion of
the rainfall of the country passes seawards in our river, and he can
measure for us the quantity of water which is actually discharged. All
this is purely Physical Geography; but when we come to ask why some
rivers flow in deep canyons, like those of the Colorado--why valleys
should widen out in one part and contract, as it were, elsewhere--why
the courses of some rivers are interrupted by waterfalls and rapids,
and many other similar questions, the physical geographer must know
something of Geology before he can give an answer. He can describe
the actual existing conditions; without the aid of Geology, he can
tell us nothing of their origin and cause. So the political geographer
can map out for us the present limits of the various countries of
Europe, but History must be invoked if we would know how those
boundaries came to be determined. The moment, therefore, the physical
geographer begins to inquire into the origin of any particular
physical feature, he enters upon the domains of the geologist. And as
he cannot possibly avoid doing so, it is quite common now to find a
good deal of the subject-matter of Geology treated of in text-books
of Physical Geography. I state this merely to show how very closely
the two sciences are interlocked. Take, for example, the configuration
of river valleys just referred to. The physical geographer recognises
the fact that a river performs work; by means of the sediment which
it carries in suspension and rolls along its course, it erodes its
bed in many places, and undermines its banks, and thus its channel is
deepened and widened. He can measure the amount of sediment which it
carries down to the sea, and the quantity of saline matters which its
waters hold in solution: and knowing that all these substances have
been abstracted from the land, he is able to estimate approximately
the amount of material which is annually transferred from the surface
of the drainage-area involved. He discovers this to be so relatively
enormous that he has no difficulty in believing that the valleys
in which rivers flow might have been hollowed out by the rivers
themselves. But, without trespassing further into the geologist's
domains, he cannot go beyond this: and you will at once perceive that
something more is required to prove that any particular valley owes its
origin to the erosive action of running water. Suppose someone were
to suggest to him that his river-valley might be a minor wrinkle in
the earth's crust caused by earth-movements, or that it might indicate
the line of a fissure or dislocation, due to some comparatively recent
convulsion--how could his computation of the amount of material at
present carried seawards by the river prove such suggestions to be
erroneous? And what light could it throw upon the origin of the
varied configuration of the river-valley--how would it explain the
presence or absence of cascades and rapids, of narrow gorges and open
expanses? None of these phenomena can be interpreted and accounted
for without the aid of the geologist: without some knowledge of rocks
and rock-structures, the origin of the earth's surface-features
is quite inexplicable. To give an adequate explanation of all the
surface-features of a country in detail would of course require a
profound study of Geology; but a general acquaintance only with its
elementary facts is quite sufficient to enable us to form a reasonable
and intelligent view of the cause and origin of the main features
of the land as a whole. Thus a few lessons in elementary Geology
would make clear to any child how rivers have excavated valleys, why
cataracts and gorges occur here, and open valleys with gently-flowing
waters elsewhere.

Let me select yet another example to show how dependent Physical
Geography is upon Geology. The physical geographer, in describing the
features of the land, tells us how the great continental areas are
traversed in various directions by what he calls mountain-chains. Thus,
in speaking of America, he tells us that it may be taken as a type
of the continental structure--namely a vast expanse of land, low or
basin-like in the interior, and flanked along the maritime regions by
elevated mountain borders--the highest border facing the deepest ocean.
He points out further that the great continental areas are crossed from
west to east by well-marked depressions, to a large extent occupied
by water. Thus Europe is separated from Africa by the Mediterranean,
a depression which is continued eastward through the Black Sea into
the Aralo-Caspian area. South America is all but cut away from North
America, while Australia is separated from Asia by the East India Seas.
We find, in fact, all over the world that well-marked natural features
are constantly being repeated. Not only do the great land-masses
of the globe bear certain resemblances to each other, but even in
their detailed structure similar parallelisms recur. The physical
geographer notes all these remarkable phenomena, but he can give us
no clue to their meaning. He may describe with admirable skill the
characteristic features of plains and plateaux, of volcanic mountains
and mountain-chains, but he cannot tell us why plains should occur
here and mountains there; nor can he explain why some mountains, such
as those of Scotland or Norway, differ so much in configuration from
the Alps and the Pyrenees. The answer to all these questions can only
be given by Geology. It is from this science