chap, vi.] GEOGRAPHICAL AND GEOLOGICAL CHANGES. 
97 ’ 
New Zealand. In North America there are immense coal 
fields in Nova Scotia and New Brunswick, from Pennsylvania 
southward to Alabama, in Indiana and Illinois, and in Missouri ; 
and there is also a true coal formation in South Brazil. This 
wonderfully wide distribution of coal, implying, as it does, a 
rich vegetation and extensive land areas, carries back the proof 
of the persistence and general identity of our continents to a 
period so remote that none of the higher animal types had 
probably been developed. But we can go even further back 
than this, to the preceding Devonian formation, which was 
almost certainly an inland deposit often containing remains 
of fresh-water shells, plants, and even insects ; while Professor 
Ramsay believes that he has found “ sun-cracks and rain- 
pittings ” in the Longmynd beds of the still earlier Cambrian 
formation. 1 If now, in addition to the body of evidence here 
adduced, we take into consideration the fresh-water deposits 
that still remain to be discovered, and those extensive areas 
where they have been destroyed by denudation or remain 
deeply covered up by later marine or volcanic formations, we 
cannot but be struck by the abounding proofs of the permanence 
of the great features of land and sea as they now exist ; and we 
shall see how utterly gratuitous, and how entirely opposed to all 
the evidence at our command, are the hypothetical continents 
bridging over the deep oceans, by the help of which it is so 
often attempted to cut the Gordian knot presented by some 
anomalous fact in geographical distribution. 
Oceanic Islands as Indications of the Permanence of Continents 
and Oceans. — Coming to the question from the other side, 
Mr. Darwin has adduced an argument of considerable weight 
in favour of the permanence of the great oceans. He says 
(i Origin of Species, 6th Ed. p. 288): “Looking to existing oceans, 
which are thrice as extensive as the land, we see them studded 
with many islands ; but hardly one truly oceanic island (with 
the exception of New Zealand, if this can be called a truly 
oceanic island) is as yet known to afforl even a fragment of 
any Palaeozoic or Secondary formation. Hence we may perhaps 
infer that during the Palaeozoic and Secondary periods neither 
1 Physical Geography and Geology of Great Britain , 5th Ed. p. Gl. 
H 
