526 071 the Dispersion and 



requires the lapse of ages to transform a barren rock into a 

 state fit to support man, and to supply his numerous wants. 



The remains of vegetables belonging to an antediluvian 

 world are found in the slate formation, and consist principally 

 of ferns, palms, grasses, reeds, &c. ; but these forms, though 

 they cannot be referred to any known species of plants, yet 

 have so much the appearance of tropical productions, that we 

 must admit the existence of a much greater heat at the sur- 

 face of the earth than at the present day ; and this heat must 

 have been distributed over all the zones, since these forms are 

 found to exist in slate formations in all parts of the earth. 

 {Philosophy of Plants, p. 276., by Decandolle and Sprengel.) 

 Whether, as was the opinion of Linnaeus, only one species in 

 each genus was originally created, we cannot positively prove 

 or deny. 



We will now proceed to a part of our subject well worthy 

 of the most earnest attention, as in no other branch of nature 

 is the Divine Providence more plainly seen ; namely, the pro^ 

 gress of vegetation. Mosses and lichens (at least in the tem- 

 perate zones) first fix their insinuating fibres in the crevices of 

 the rocks ; and as these die, and are again reproduced, a light 

 vegetable soil is deposited, which in time becomes of sufficient 

 depth to support grasses and other herbaceous plants : and at 

 length, in the course of ages, the desert rock becomes a ver- 

 dant meadow. The fruit of some tree is cast up by the waves, 

 or dropped by birds : thus forests are gradually produced, till 

 the island becomes fitted for the residence of man, who along 

 with him introduces his domestic animals : and thus the once 

 naked rock becomes a thriving colony. In the northern part 

 of the temperate zones, as we have before observed, the cryp- 

 togamic plants are the first that cover the stony crust of the 

 globe; the lichens and mosses, that display their foliage 

 beneath the snows, are succeeded by grasses and other pha- 

 nerogamous plants. This is the order of vegetation in the 

 northern and temperate zones ; but when we advance to the 

 torrid zone, and between the tropics, the progressive stages 

 are different. (Humboldt's Personal Na?Tative, vol. i. p. 262.) 

 We there find, it is true, whatever some travellers may have 

 asserted to the contrary, not only in the mountains, but also 

 in the humid and shady places, almost on a level with the 

 ocean, Funaria, Dicranum, and i?ryum ; and these genera 

 among their numerous species exhibit several which are com- 

 mon to Lapland, the Peak of Teneriffe, and the Blue Moun- 

 tains of Jamaica. Nevertheless, in general, it is not by mosses 

 and lichens that vegetation in countries near the tropics begins. 

 In the Canary Islands, as well as in Guiana, and on the rocky 



