14 Atlantis and Lemuria : [January, 
great ocean basins occupied their present position through 
all geological time,” as is maintained by Mr. A. R. Wallace, 
Mr. Murray of the Challenger Expedition, Professors Dana, 
Le Conte, and Agassiz ; or has a complete change of land 
and sea taken place over and over again, as was held by 
Lyell and many of the elder geologists ? This latter view 
has been very ably supported by Mr. Reade in the treatise 
now before us, and is strongly controverted by Mr. Wallace in 
his “ Geographical Distribution of Animals,” his “ Austral- 
asia,” and especially in his most recent work, “ Island 
Life.” Both authors seem agreed that “ every foot of dry 
land has undoubtedly, at one time or other, formed part of 
a sea-bottom,” but the converse proposition is not admitted. 
Mr. Reade argues that as “ subaerial waste of land is the 
main source of the detritus of which the rocks are built, it 
follows that where the marine deposits were going on equi- 
valent land must have existed somewhere,” and that “ the 
more we limit the area of the oscillation of land and sea, 
the more difficult the explanation of the phenomena of geo- 
logy becomes.” 
Mr. Wallace, on the other hand, urges that the stratified 
rocks of our continents, consisting of sandstones, limestones, 
and conglomerates, must have been deposited in the shallow 
water within a comparatively short distance from the shore. 
He shows that the materials “denuded from the land and carried 
down as sediment by rivers are almost always confined within 
a distance of 50 to 100 miles of the coast, the finest mud 
only being carried 150 or rarely 200 miles.” The deposits 
in mid-ocean consist mainly of “ the shells of minute calca- 
reous or siliceous organisms, with some decomposed pumice 
and volcanic dust.” The deep-sea deposits differ in their 
chemical composition from any strata known to geologists, 
whilst the littoral accumulations approximate closely to 
chalk. Strata which had been formed in mid-sea would be 
characterised by the absence of vegetable remains. Yet if 
we go back from the miocene even to the palaeozoic age we 
find embedded in the rocks the remains of plants and of 
animals peculiar to the land, to lakes, or to shallow seas. 
Further, as we have mentioned above in case of the Azores, 
the true oceanic islands, remote from the shores of the pre- 
sent continents, have not “ preserved any fragments of the 
supposed ancient continents, nor of the deposits which must 
have resulted from their denudation during the whole period 
of their existence.” Mr. Darwin contends* that had such 
continents existed, palaeozoic and secondary formations 
* Origin of Species, p. 288 (6th edition). 
