106 The American Naturalist. [February, 
EAH 
G LThe general climate of any portion of the earth’s surface is 
determined by latitude, i. e., by the amount of heat received 
from the sun. But there are other influences which combine 
to modify the climate of any given locality. The most im- 
portant are the extent and position of the bodies of land, the 
heighth and trend of mountain ranges, and the relation be- 
tween ocean and air currents. If all these conditions remain un- 
changed fora very long period, no great diversity of climate will 
effect the locality. But any disturbing influence, destroying the 
relations between the conditions mentioned must, in rerum 
nature, effect the climate of the entire earth toa certain extent. 
Of strictly terrestrial causes there are none so potent to bring 
about this result as great earth movements, changing the rela- 
tion between the continents and seas, thus modifying the ocean 
currents, and by presenting barriers in the form of high 
mountain ranges, interfering with the courses of the prevailing 
winds. In view of the fact that astronomical causes of the 
changes of geologic climates are not capable of practical demon- 
stration, while the terrestrial or land movement theory not 
only is capable of such proof, but already such evidence has 
been collected to indicate at least a time relation between the 
main land disturbances and the most important climatic 
changes, I shall consider only the latter hypothesis in the pres- 
ent discussion. 
If the peninsula of Florida were uplifted several thousand 
feet into a high narrow plateau, and then dissevered by the 
erosion of deep valleys into separate mountain peaks and 
ridges, the present warm temperate and subtropical flora and 
fauna would largely disappear. With the production of a 
rocky sea-cliff about its borders and the destruction of the 
swamps and marshes, the palmetto and alligator, each the 
most characteristic portion of the Floridian flora and fauna, 
would be eliminated; forced to migrate or become extinct, 
With them would go the destruction of many other animals 
and plants. The geologist who would make a study of the 
region one million years hence, would find such a great con- 
trast in the fossil remains enclosed in the strata laid down near 
the coast now and those after the uplift, that he would be con- 
