184 ORIGIN OP LIFE IN AMERICA 



existing coast line of the Atlantic States south of Massachu- 

 setts was submerged (Fig. 14). I look upon the indigenous 

 animals a,nd plants of Bermuda as relicts of an ancient fauna 

 and flora. I hold, moreover, that Bermuda furnishes us with 

 one of the most instructive facts of the exceedingly slow 

 change that many species of animals and plants undergo 

 through successive geological ages, and that it does not sup- 

 port the theory advocated by Dr. Wallace that many organisms 

 possess the power of crossing seven hundred miles of open 

 sea. 



The geology of Bermuda, so far as the visible structure is 

 concerned, is identical with that of the Bahamas, except that 

 the coral reefs are of greater importance in the latter. The 

 rocks in both are limestone, and red clays resulting from its 

 decomposition. Nearly all the rocks of Bermuda above 

 sea-level, and to a considerable depth below it, are made up of 

 wind-drifted shell sand with very little material derived from 

 corals and other organisms. These materials, according to 

 Professor Verrill, when consolidated, form a true aeolian lime- 

 stone. The island is surrounded by coral reefs in such a 

 manner as to give it the appearance of an atoll of the Pacific 

 Ocean. It was actually regarded as such by Professor Eice.* 



The greater Bermuda or "Pliocene Bermuda" as it has 

 been called, which was once dry land, had an area of about two 

 hundred and thirty square miles. That this greater Bermuda 

 represents an older land surface was revealed during the exca- 

 vations made in 1870 for harbour works. These extended to 

 over fifty feet below sea-water level. At a depth of forty- 

 six feet, as Mr. Jones f telle ug, a stratum of peat and red 

 earth two feet thick was found, containing the vertical stumps 

 of cedar trees. This again rested on hard aeolian limestone, 

 containing fossil land shells of the genus Poeoilozonites. 

 There is clear evidence, therefore, of a subsidence of the 

 land to the extent of at least fifty feet. A re-elevation to 

 that extent would nearly restore the island of greater 

 Bermuda. Beyond this, in a SQuth-westward direction, several 

 shallows have been detected, all being surrounded by great 



* Eioe, W. N., "Geology of Bermuda," p. 9. 



t Jones, J. M., " Eecent Observations in Bermudas," p. 262. 



