CHAPTER VI. 
GEOGRAPHICAL AND GEOLOGICAL CHANGES : THE 
PERMANENCE OF CONTINENTS. 
Changes of Land and Sea, their nature and extent — Shore-deposits and 
stratified Rocks — The Movements of Continents — Supposed Oceanic 
formations ; the Origin of Chalk — Fresh-water and Shore-deposits as 
proving the permanence of Continents— Oceanic Islands as indications 
of the permanence of Continents and Oceans — General stability of 
Continents with constant change of form — Effect of Continental 
Changes on the Distribution of Animals — Changed distribution proved 
by the extinct Animals of different epochs — Summary of evidence 
for the general permanence of Continents and Oceans. 
The changes of land and sea which have occurred in 
particular cases will be described when we discuss the origin 
and relations of the faunas of the different classes of islands. 
We have here only to consider the general character and extent 
of such changes, and to correct some erroneous ideas which are 
prevalent on the subject. 
Changes of Land and Sea , their nature and extent . — It is a very 
common belief that geological evidence proves a complete change 
of land and sea to have taken place over and over again. Every 
foot of dry land has undoubtedly, at one time or other, formed 
part of a sea-bottom, and we can hardly exclude the surfaces 
occupied by volcanic and fresh-water deposits, since, in many 
cases, if not in all, these rest upon a substratum of marine 
formations. At first sight, therefore, it seems a necessary 
inference that when the present continents were under water 
there must have been other continents situated where we now 
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