Even in the case of slow-breeding animals, which unite for each birth, we must not overrate the effects of intercrosses in retarding natural selection; for I can bring a considerable catalogue of facts, showing that within the same area, varieties of the same animal can long remain distinct, from haunting different stations, from breeding at slightly different seasons, or from varieties of the same kind preferring to pair together.
In a confined or isolated area, if not very large, the organic and inorganic conditions of life will generally be in a great degree uniform; so that natural selection will tend to modify all the individuals of a varying species throughout the area in the same manner in relation to the same conditions.
Fortunately for the pursued, the light of the moon, while it shed a flood of mild luster upon the little area around the ruin, was not sufficiently strong to penetrate the deep arches of the forest, where the objects still lay in deceptive shadow.
It was not long, however, before the restless savages were heard beating the brush, and gradually approaching the inner edge of that dense border of young chestnuts which encircled the little area.
These relatively small areas
of ocean follow the general lines of the continents of the outer world.
Ready to search a land area of 124,110,000 square miles for my friends, my incomparable mate, and good old Perry!
Nor is this strange, for Pellucidar, in its land area, is immense, while the human race there is very young and consequently far from numerous.
The isolation of the Kaolians is rendered almost complete by the fact that no waterway connects their land with that of any other nation, nor have they any need of a waterway since the low, swampy land which comprises the entire area of their domain self-waters their abundant tropical crops.
Occasional areas of firm sod gave us intervals of rest from the arduous labor of traversing this gorgeous, twilight swamp, and it was upon one of these that I finally decided to make camp for the night which my chronometer warned me would soon be upon us.
The air was filled with dust and flying bits of vegetation and when the storm carried her across an irrigated area
of farm land she saw great trees and stone walls and buildings lifted high in air and scattered broadcast over the devastated country; and then she was carried swiftly on to other sights that forced in upon her consciousness a rapidly growing conviction that after all Tara of Helium was a very small and insignificant and helpless person.
I want you to take notice," he added to the others, as he gently touched the live-end of his fresh cigar to the area
of dark skin above and between the steward's eyes.
Near the head of the lagoon I was much surprised to find a wide area
, considerably more than a mile square, covered with a forest of delicately branching corals, which, though standing upright, were all dead and rotten.