Vor. IJ STEWART—BOTANY OF THE GALAPAGOS ISLANDS 239 
The deposit rests on a nearly level and extensive lava flow with a 
greatest observed elevation of about 60 ft. above the present sea-level. 
Where the sands have been hardened into crusts in thin layers, they 
carry abundant and nicely preserved specimens of marine molluscan 
and echinoid forms. 
“Toward the interior and higher levels of the island the deposit 
exists only as little island-like exposures which have escaped the great 
recent flow of lava that has poured down over this old beach to conceal 
its exact and higher levels of distribution. This deposit should be 
placed as late Pliocene or early Quarternary.” 
Outside of the few localities mentioned above, there is no 
evidence of a general elevation, so far as has been observed, 
and it is not improbable that during the period of general sub- 
sidence there might have been times in which it ceased and 
during which local elevation took place. Mr. Ochsner states 
further: “I am much in favor of the theory of subsidence. 
With additional thought and study given the matter I feel that 
the testimony of my collected facts and observations will go to 
prove this theory nearly a fact.” 
In conclusion it might be said that however true Dr. Baur’s 
theory may be in regard to the union of the islands into one 
large one, there is no strong evidence to show that they were 
ever connected with the mainland. The biological conditions 
at the present time are more against this theory than for it. 
The botanical conditions do not offer absolute proof that the 
islands have ever been connected with each other, but the 
weight of the evidence is more in favor of this theory than 
against it. 
ORIGIN OF THE FLORA 
If it be assumed that the Galapagos Islands are of 
oceanic origin, there are but three means by which seeds and 
spores could have been brought to the islands, outside of the 
agency of man. These are: winds, oceanic currents, and 
migratory birds. 
Winds 
If winds were an important agent in bringing seeds and 
spores to these islands, those families of plants which have the 
smallest seeds and spores would be the most apt to be dis- 
tributed in this way. Of all the families of vascular plants 
none are better adapted for wind distribution than are the ferns. 
Such being the case, there should be a larger number of species 
of ferns on the islands common to the region from which the 
prevailing winds blow than from any other. As the winds 
