Chapter VIII

ON LUNAR CRATERS. 89
Use of term Crater for Terrestrial and Lunar Formations—Truly
Volcanic Nature of Lunar Craters—Terrestrial and Lunar
Volcanic Areas compared—Similarity—Difference only in
Magnitude—Central Cone—Found in great and small Lunar
Craters—Formative Process of Terrestrial Volcanoes—Example
from Vesuvius—Vast Size of Lunar Craters—Reasons
assigned—Origin of Moon’s Volcanic Force—Aqueous Vapour
Theory untenable—Expansion upon Solidification
Theory—Formative Process of a Lunar Crater—Volcanic
Vent—Commencement of Eruption—Erection of
Rampart—Hollowing of Crater—Formation of Central Cone—Of
Plateau—Various Heights of Plateaux—Coneless
Craters—Filled-up Craters—Multiple Cones—Craters on
Plateau—Double Ramparts—Landslip Terraces—Rutted
Ramparts—Overlapping and Superposition of
Craters—Source-Connection of such—Froth-like Aggregations
of Craters—Majestic Dimensions of Larger Craters

CHAPTER IX.
ON THE GREAT RING-FORMATIONS NOT MANIFESTLY VOLCANIC. 117
Absence of Central Cones—Vast Diameters—Difficult of
Explanation—Hooke’s Idea—Suggested Cause of True
Circularity—Scrope’s Hypothesis of Terrestrial
Tumescences—Rozet’s Tourbillonic Theory—Dana’s Ebullition
Theory

CHAPTER X.
PEAKS AND MOUNTAIN RANGES. 124
Paucity of extensive Mountain Systems on Moon—Contrast with
Earth—Lunar Mountains found in less disturbed
Regions—Lunar Apennines, Caucasus, and Alps—Valley of
Alps—“Crag and Tail” Contour—Isolated Peaks—How
produced—Analogy from Freezing Fountain—Terrestrial
Counterparts and their Explanation by Scrope—Blowing Cone
on Teneriffe—Comparative Gentleness of Mountain-forming
Action—Relation between Mountain Systems and Crater
Systems—Wrinkle Ridges

CHAPTER XI.
CRACKS AND RADIATING STREAKS. 133
Description—Divergence from Focal Craters—Experimental
Explanation of their Cause—Radial Cracking of
Crust—Outflow of Matter therefrom—Analogy from “Starred”
Ice—No Shadows cast by Streaks—Their probable Slight
Elevation—Open Cracks—Great Numbers—Length—Depth—In-fallen
Fragments—Shrinkage a Cause of Cracks—Lateness of their
Production