Chapter I: Front Matter

Transcriber Note

Text emphasis denoted by _Italics_ and =Bold.= Whole and fractional parts of numbers as 123-4/5.

THE ANCIENT VOLCANOES OF GREAT BRITAIN

THE

ANCIENT VOLCANOES

OF

GREAT BRITAIN

BY

SIR ARCHIBALD GEIKIE, F.R.S.

D.C.L. Oxf., D.Sc. Camb., Dubl.; LL.D. St. And. Edinb.

DIRECTOR-GENERAL OF THE GEOLOGICAL SURVEY OF GREAT BRITAIN AND
IRELAND; CORRESPONDENT OF THE INSTITUTE OF FRANCE; OF THE
ACADEMIES OF BERLIN, VIENNA, MUNICH, TURIN, BELGIUM,
STOCKHOLM, GÖTTINGEN, NEW YORK; OF THE IMPERIAL MINERALOGICAL
SOCIETY AND SOCIETY OF NATURALISTS ST. PETERSBURG; NATURAL
HISTORY SOCIETY, MOSCOW; SCIENTIFIC SOCIETY, CHRISTIANIA;
AMERICAN PHILOSOPHICAL SOCIETY; OF THE GEOLOGICAL
SOCIETIES OF LONDON, FRANCE, BELGIUM, STOCKHOLM, ETC.

WITH SEVEN MAPS AND NUMEROUS ILLUSTRATIONS

IN TWO VOLUMES

VOL. II

London
MACMILLAN AND CO., Limited
NEW YORK: THE MACMILLAN COMPANY

1897

_All rights reserved_

CONTENTS

CHAPTER XXIX

The Carboniferous Volcanoes of England

PAGE

The North of England: Dykes, Great Whin Sill--The Derbyshire
Toadstones--The Isle of Man--East Somerset--Devonshire 1

CHAPTER XXX

The Carboniferous Volcanoes of Ireland

King's County--The Limerick Basin--The Volcanic Breccias of
Doubtful Age in County Cork 37

BOOK VII

THE PERMIAN VOLCANOES

CHAPTER XXXI

The Permian Volcanoes of Scotland

Geographical Changes at the Close of the Carboniferous Period--Land
and Inland-Seas of Permian time--General Characteristics and
Nature of the Materials erupted--Structure of the several
Volcanic Districts: 1. Ayrshire, Nithsdale, Annandale; 2.
Basin of the Firth of Forth 53

CHAPTER XXXII

Permian Volcanoes of England

The Devonshire Centre--Eruptive Rocks of the Midland Coal-fields 94

BOOK VIII

THE VOLCANOES OF TERTIARY TIME

CHAPTER XXXIII

Vast lapse of time between the close of the Palæozoic and beginning
of the Tertiary Volcanic Eruptions--Prolonged Volcanic
Quiescence--Progress of Investigation among the Tertiary
Volcanic Series of Britain 107

CHAPTER XXXIV

The System of Dykes in the Tertiary Volcanic Series

Geographical Distribution--Two Types of Protrusion--Nature of
component Rocks--Hade--Breadth--Interruptions of Lateral
Continuity--Length--Persistence of Mineral Characters 118

CHAPTER XXXV

The System of Dykes--_continued_

Direction--Termination upward--Known vertical extension--Evidence
as to the movement of the Molten Rock in the
Fissures--Branches and Veins--Connection of Dykes with
Intrusive Sheets--Intersection of Dykes--Dykes of more than
one infilling--Contact metamorphism of the Dykes--Relation of
the Dykes to the Geological Structure of the Districts which
they traverse--Data for estimating the Geological Age of the
Dykes--Origin and History of the Dykes 145

CHAPTER XXXVI

The Plateaux

Nature and Arrangement of the Rocks: 1. Lavas.--Basalts, Dolerites,
Andesites--Structure of the Lavas in the Field--2. Fragmental
Rocks.--Agglomerates, Conglomerates, and Breccias--Tuffs and
their accompaniments 181

CHAPTER XXXVII

The Several Basalt-Plateaux and their Geological History--Antrim,
Mull, Morven and Ardnamurchan 199

CHAPTER XXXVIII

The Basalt-Plateau of the Parish of Small Isles--Rivers of the
Volcanic Period 215

CHAPTER XXXIX

The Basalt-Plateaux of Skye and of the Faroe Isles 249

CHAPTER XL

The Modern Volcanoes of Iceland as illustrative of the Tertiary
Volcanic History of North-Western Europe 260

CHAPTER XLI

The Eruptive Vents of the Basalt-Plateaux

Vents filled with Basalt or other Lava-form Rock--Vents filled
with Agglomerate 270

CHAPTER XLII

The Basic Sills of the Basalt-Plateaux 298

CHAPTER XLIII

The Bosses and Sheets of Gabbro

Petrography of the Rocks--Relations of the Gabbros to the other
members of the Volcanic series--Description of the Gabbro
districts--Skye 327

CHAPTER XLIV

The Bosses and Sheets of Gabbro in the Districts of Rum,
Ardnamurchan, Mull, St. Kilda and North-East Ireland.
History of the Gabbro Intrusions 349

CHAPTER XLV

The Acid Rocks

Their Petrography--Their Stratigraphical Position and its
Analogies in Central France 364

CHAPTER XLVI

Types of Structure in the Acid Rocks--Bosses 378

CHAPTER XLVII

The Acid Bosses of Mull, Small Isles, St. Kilda, Arran, and
the North-East of Ireland 395

CHAPTER XLVIII

The Acid Sills, Dykes and Veins 430

CHAPTER XLIX

The Subsidences and Dislocations of the Plateaux 447

CHAPTER L

Effects of Denudation 455