CONTRIBUTIONS FROM THE BERMUDA BIOLOGICAL STATION 

 FOR RESEARCH, No. 69. 



THE ALGAE OP BERMUDA. 



By Frank S. Collins and Alphbus B. Hbrvet. 



Bermuda consists of a little group of islands of not more than twenty 

 square miles of dry land, lying in latitude 32° 14'-32° 23' north and 

 longitude 64° 38-64° 53' west, about -700 miles southeast of New 

 York, and 600 miles east of the coast of South Carolina. They are 

 some three or four hundred mUes south and east of the Gulf Stream. 

 This situation accounts for the very marked uniformity as well as the 

 mildness of the climate of the islands. 



All of Bermuda now above sea level consists of limestone, from a 

 fine sand to hard crystalline rock. The lime comes from the various 

 organisms inhabiting the water, in part animal but more largely 

 vegetable; ^ many of these lime-producing algae are included in the 

 following pages, but Lithothamnium and its allies, stony algae be- 

 longing to the Florideae, which furnish the larger part of the material, 

 we have not been able to include here. The fine powder formed from 

 the remains of these various organisms is carried by the wind and 

 spread out over the ground. Rainwater dissolves a certain amount 

 of it, which when the water dries up is deposited and acts as a cement. 

 Crystallization goes on more or less within the masses after formation, 

 and so some parts become much harder than others. Erosion from 

 rain or from the sea is continually going on, and its action being 

 greater in the softer than in the harder parts, we have a great variety 

 of fantastic forms along the shore, and many caves underground. 



It has long been supposed that there was a core of solid rock under 

 the limestone, but only recently have any definite data been obtained 

 in regard to it. Pirsson, 1914, gives the particulars in regard to a 

 boring made in the hope, which was not fulfilled, of obtaining a supply 

 of fresh water. The boring was in Southampton parish, about a mile 

 west of Gibbs HUl Lighthouse, 135 feet above sea level. To 380 feet 



1 For a summary of the results of investigations as to the parts taken in the 

 formation of "coral" islands, by animal and vegetable organisms, see Howe, 

 1912. 



