‘ Notice6f the. Wonilérs-of Geology. 15 
“ But ought we to rest content in the assumption that all these 
wonderful manifestations of Creative Intelligence were solely de- 
signed to contribute to our physical necessities and gratifications ? 
Say, rather, that this display of beauty, power, and goodness, was 
designed to fill the soul with high and holy thoughts—to call 
forth the exercise of our reasoning powers—to excite in us those 
ardent and lofty aspirations after truth and knowledge, which ele- 
vate the mind above the sordid and petty concerns of life, and 
give us a foretaste of that high destiny, which we are instructed 
to hope may be our portion hereafter ! 
“G theory of Leibnitz.—If we extend our views be- 
yond the limits of strict induction, and venture to speculate on 
the condition of our globe in the dawn of its existence, and in 
those remote periods of which the physical characters are in- 
scribed on the rocks and mountains, it appears to me that the 
theory of Leibnitz, which embraces the original nebular condi- 
tion of the solar system, and assumes a former incandescent state 
of this planet, and its gradual refrigeration, is the only hypothe- 
sis in harmony with the present state of astronomical and geolo- 
gical knowledge. The prevalence of a higher temperature in 
northern latitudes during the deposition of the s 
tions, was indicated by the fossil remains of animals and plants 
of a tropical character. If we admit of a progressive cooling of 
the earth, we necessarily infer that in the most ancient epochs, 
the influence of the internal heat upon the earth’s surface was 
very considerable, and that it gradually decreased, till it arrived 
at the present condition of things, in which the surface tempera- 
ture is scarcely, if at all, affected by radiation from within. As- 
suming then as an established theory, what at present, perhaps, 
must only be regarded as a highly philosophical and probable 
speculation, we can readily understand that during the secondary 
geological eras, the temperature of the surface may have been 
so augmented by a supply of heat from an internal source, as 
to have maintained a climate possessing the conditions required 
for the existence of corals in the seas, and of forests of palms 
and tree ferns, and swarms of reptiles, on the islands and conti- 
nents of northern latitudes.* The climate of particular latitudes 
ere of the p t state of geological theory in Phillips’s 
* See an 
Treatise on Geology. ~ 
