chap, vi.] GEOGRAPHICAL AND GEOLOGICAL CHANGES. 101 
Summary of Evidence for the General Permanence of Continents 
and Oceans . — As this question of the permanence of our 
continents lies at the root of all our inquiries into the past 
changes of the earth and its inhabitants, and as it is at present 
completely ignored by many writers, and even by naturalists of 
eminence, it will be well to summarise the various kinds of 
evidence which go to establish it. 1 We know as a fact that all 
sedimentary deposits have been formed under water, but we 
also know that they were largely formed in lakes or inland 
seas, or near the coasts of continents or great islands, and that 
deposits uniform in character and more than 150 or 200 miles 
wide were rarely, if ever, formed at the same time. The further 
we go from the land the less rapidly deposition takes place, 
hence the great bulk of all the strata must have been formed 
near land. Some deposits are, it is true, continually forming in 
the midst of the great oceans, but these are chiefly organic and 
increase very slowly, and there is no proof that any part of the 
series of known geological formations exactly resembles them. 
Chalk, which is still believed to be such a deposit by many 
naturalists, has been shown, by its contained fossils, to be a 
1 In a review of Mr. Reade’s Chemical Denudation and Geological Time 
in Nature (Oct. 2nd, 1879) the writer remarks as follows: — “One of the 
funny notions of some scientific thinkers meets with no favour from Mr. 
Reade, whose geological knowledge is practical as well as theoretical. They 
consider that because the older rocks contain nothing like the present red 
clays, &c., of the ocean floor, that the oceans have always been in then- 
present positions. Mr. Reade points out that the first proposition is not 
yet proved, and the distribution of animals and plants and the fact that 
the bulk of the strata on land are of marine origin are opposed to the hypo- 
thesis.” We must leave it to our readers to decide whether the “notion” 
developed in this chapter is “ funny,” or whether such hasty and superficial 
arguments as those here quoted from a “ practical geologist ” have any 
value as against the different classes of facts, all pointing to an opposite 
conclusion, which have now been briefly laid before them, supported as 
they are by the expressed opinion of so weighty an authority as Professor 
Archibald Geikie, who, in the lecture already quoted says: — “From all 
this evidence we may legitimately conclude that the present land of the 
globe, though formed in great measure of marine formations, has never 
lain under the deep sea ; but that its site must always have been near 
land. Even its thick marine limestones are the deposits of comparatively 
shallow water.” 
