RELATIVE GEOLOGICAL ANTIQUITY OF TREES. 147 



flowers of plants are gigantic, and their colors are splendid 

 and dazzling. At the poles, the plants sink down to the 

 condition of dwarfs ; their foliage is tough and coriaceous, and 

 of a dark and sombre green, gloomy as the long night of the 

 polar world. In some cases even here the northern lights, 

 and the reflection of the wonderful midnight sun, produce in 

 some of the plants an unexpected splendor of coloring. In 

 the steady light which comes from the sun as he circulates 

 about the horizon for weeks, the grasses and other plants 

 assumed a softened green. But far purer and higher are the 

 colors of the flowers. The Trientalis and Anemone, which in 

 temperate climates produce white flowers, steep themselves in 

 the beams of the midnight sun of the deepest red. 



Now if the organism of the plants thus varies on the earth's 

 surface, from the valley to the mountain summit, and from 

 the equator to the poles, then it is plain that any physical 

 revolutions which shall, in the course of ages, change the 

 features of the land, must at the same time produce a change 

 in its flora. We know that when forests are cut down in 

 America, the plants which grew beneath their shade become 

 exhausted and die out ; so, also, swamp plants and trees dis- 

 appear when the soil is -drained of its superfluous water. 

 Would not the same results take place if such changes were 

 brought about in the course of ages through the operation 

 of the ordinary forces of Nature? It is certain that land 

 cannot be first elevated and then depressed below the surface 

 of old Ocean, without great changes in temperature, and that 

 many species would in this way naturally perish when the 

 conditions became unsuited to their growth. Fossil plants 

 may be truly regarded as the remains of a system of vegeta- 

 ble life, developed under external conditions which are no 

 longer the same in any part of the world. 



But there are indestructible organic features which connect 

 the flora of the present with that of former ages. Not only 

 individuals, but even species, genera, and whole orders, have 

 perished ; but there prevail, in the present Creation, forms or 

 types which existed in the most remote geological periods. 

 This proves indisputably that there are certain persistent 



