SEWARD: FOSSIL CLIMATES. 151 
referred to a New Zealand forest as the nearest approach to the 
evergreen forests of the Paleozoic period. Even here we may 
remember how tree ferns almost overhang the terminal moraines of 
glaciers ; a striking caution, which should temper our rashness in 
settling climatal questions. 
In dealing with these older plants—and, indeed, with all fossils— 
one cannot be too mindful of the many instances in the vegetable 
and animal kingdoms which prove how closely-related species may 
live under very different conditions of climate. It is well known how 
Palms, generally characteristic of warm countries, are represented by 
species growing in northern latitudes in Europe ; in the Himalayas, 
too, palms, bamboos, and Conifers grow in close association. Many 
land plants of the north temperate zone have been found to extend 
themselves rapidly when afforded an opportunity of spreading in 
warmer latitudes 
In the case of animals, many similar examples might be taken 
warning us against the danger of regarding a close specific relation- 
ship as a necessary mark of similar habitats. To take one instance: 
the chamois—a kind of antelope—delights in the severe cold of 
Alpine heights, the antelopes generally being inhabitants of warmer 
regions (‘ Nature,’ ia pp. 148-151, pp. 175-180; ‘The Climates 
of Past Ages,’ Neum 
This power of IS eo in plants is a subject as interesting as 
it is significant and suggestive, but we cannot now stay to describe 
the peculiar leaf-structures in certain Greenland plants, or in such as 
flourish further south in the Steppes, by which the periods of drought 
are tided over. 
Let us rapidly sketch the general conditions of climate in the past, 
noticing here and there such facts as may tend to modify some of 
the generally received ideas with regard to past temperatures. 
Leaving out of consideration the oldest periods, we plunge at once 
into the shades of a Carboniferous forest. A vast expanse of forest- 
covered swamp, or low-lying ground, thickly set with archaic types 
of vascular cryptogams, with whose protean genera one is familiar 
in the various ‘Carboniferous landscapes,’ the same genus being made 
to appear in such a garb as may best suit the theories of the 
botanical reconstructor or the artist’s conception of sylvan beauty. 
laden ‘aden with aqueous vapour, rich in carbonic pdt gas; a uniform 
Vey ie 1897. 
