386 
ORIGIN OF LIFE IN AMERICA 
moreover, is riddled with the burrows of myriads of land 
crabs, which have aided the domestic animals, to the best of 
their ability, in this work. Trinidad seems to have been 
densely wooded formerly with tree ferns, palms, etc., whereas 
living trees are now confined to the mountain tops. Among 
the ferns collected on the island by Dr. Copeland * there was 
one (Asplenium compressum) hitherto only observed in St. 
Helena. Of the fauna nothing appears to be known. 
Ascension island lies in about the middle of the southern 
Atlantic. When Darwin visited the island during his famous 
voyage round the world, he found little there of interest. A 
principal mound in the centre looks as if it were the parent of 
the lesser volcanic cones studded round the island. The sur¬ 
face is parched and barren, and everything presents a scene 
of utter desolation. Yet not only is Ascension island in¬ 
habited, the scanty pasture has even been made serviceable 
for a number of sheep, goats and cows. Ascension stands on a 
submarine bank about two hundred miles in length. It is 
probable on that account that the existing island only repre¬ 
sents the last remnant of a cluster of volcanic cones which 
rose high above the surrounding land. The surviving fauna 
and flora are extremely poor. Many of the species, like the 
centipede Scolopendra morsitans, are almost cosmopolitan in 
their range, a few also occur in Africa or South America. 
But no effort has as yet been made to conduct a thorough 
zoological and botanical survey of the island, and it is to be 
hoped that this will be accomplished before all traces of the 
ancient relicts that might still occur have been superseded 
by recent importations. At any rate, nothing of any impor¬ 
tance can be gathered from the little information we possess.f 
St. Helena, like Ascension island, is wholly volcanic in 
structure, and being, moreover, surrounded by depths up to 
17,000 feet, Dr. Wallace claims that we ought to be satisfied 
as to its being a true oceanic island and as to its owing none of 
its peculiarities to a former union with any continent or other 
distant land. But, as I have pointed out once before, the exis¬ 
tence of such a great depth of the ocean does not prove that it 
* Copeland, R., “ Insel Trinidad,” pp. 274—277. 
t Gtintlier, A., and others, “ Collection made in Ascension Island.” 
