The Evolution of Climates. — Mafiso?i. 1 1 1 
the action of geological forces in tropical areas, which is due to 
the earlier removal of glacial conditions, to the shorter dura- 
tion of the period of glaciation, to long exposure to the decom- 
posing effects of tropical rains and heat, and to the commin- 
gling of the classes of phenomena. Therefore the final battle in 
the glacial controversy must be fought in the settlement of the 
question of tropical glaciation. 
Opinions Adverse to Tropical Glaciaiio7i. 
Of the observers who have studied the geology of tropical 
regions, the following, among many others, may be cited as 
having expressed views adverse to the idea of tropical gla- 
ciation: — Charles Darwin, F. R. S., etc.,* Prof. Jno. C. Bran- 
ner,t Dr. Geo. Gardnier,$ Dr. A. R. Wallace,§ Prof. Jas. Or- 
ton,]| Prof. Jas. E. Mills,! Prof. O. E. Derby.** 
Of these, Prof. Branner may now be accepted as the leader, 
since his long residence in Brazil, extended studies and publi- 
cations justly entitle him to this position; and his conclusions 
have been accepted by Dr. A. R. Wallace, an able student of 
glacial physics.ff 
Besides these, there are many able writers and observers 
who are loth to accept any views or interpretations involving 
tropical glaciation, because no natural law has been cited to 
explain how solar energy could have been arrested and tropical 
glaciation occur. 
*Trans. Geol. Soc, Vol. VI, 2iid Series, p. 427. "Geological Ob- 
servations," N. Y. 1891, p. 428, supposes the decomposition took 
place under the sea. 
fTrans. Am. Phil. Soc, Vol. XVI, pp. 419 and 420. Nature, Vol. 
48, Oct. 19th, 1893, pp. 589 et. seq. The Journal of Geology, Vol. I, 
No. 8, pp. 753 et. seq. 
JNew Phil. Jour., Edin., XXX, 1841, 75-82. 
§Nature, Vol. 48, Oct. 19th, 1893. 
llProc. Am. As. Advancement Sci., Vol. XVIII, p. 198. 
lAm. Geologist, III, p. 361. 
**Quart. Jour. Geol. Soc, Vol. XIII, 1887, pp. 457-573. 
tt Nature, Vol. 48, Oct. 19th, 1893. 
See also authorities cited by Dr. Branner, Jour, of Geology, Vol. 
fl, No. 8, p. 771. 
