VI INTRODUCTION 



The limestone cap is formed of the debris of various lime secreting 

 animals and plants, segregated during periods of submersion, comminuted 

 and eroded by wind and wave action during periods of emergence. In 

 the course of a deep well boring, made a few years ago in the parish of 

 Southampton, at a point about 200 feet above sea level, this limestone cap 

 was penetrated and found to rest upon rocks of volcanic origin. '"'' Of the 

 1400 feet penetrated by the boring, the first 360 feet are in the limestones 

 of the usual character known in Bermuda. Below them for 200 feet, soft 

 yellowish to brown, often clay-like rocks are met, whose nature indicates 

 that they are more or less decomposed volcanic tuffs. Below them blackish 

 to gray compact volcanic rocks are found, of andesitic and basaltic appear- 

 ance. The study of the section made from a chip indicates that this is a 

 lava, and, though considerably altered, an augite-andesite. This rock con- 

 tinues without essential change in character for the further 800 feet pene- 

 trated."* It was a great disappointment to the promoters of this inter- 

 esting boring that no supply of water was obtained. 



The limestone contains locally numerous caves and caverns, formed by 

 the slow leaching of the more soluble portions by the infiltration of rain 

 water. Some of these caves are of large extent and of great interest and 

 beauty. The surface erosion of the limestone has been very irregular, 

 forming many picturesque cliffs. The most rugged region is the neck of 

 land separating Castle Harbor from Harrington Sound, and here the larger 

 caves occur. Many of the native plants are now restricted to this region, 

 presumably because it has been less modified by man than other parts of 

 Bermuda, and also because the numerous pockets of soil in dense shade pro- 

 vide a suitable home for many of the rarer species. Governor Lefroy 

 thought this (Walsingham tract) geologically older than the rest of the 

 land area, " the last surviving contemporary of former Bermudas that have 

 disappeared, whose surface rocks form the reefs that fill Castle Harbor 

 and both the sounds."t 



The soil is calcareous throughout its extent, sandy over parts of the 

 island, especially along the south coasts. The numerous swales among the 

 hills contain a rich,, red, slightly clayey soil, resulting from the leaching of 

 the hillsides and the deposit in the swales of the less soluble portions of 

 the rock; the soil of fresh-water marshes is black or brown, covered by 

 humus, and is either sandy or slightly clayey. There are, locally, salt 

 marshes and mangrove swamps, and, especially along the coasts, some 

 stretches of white sand-beaches. 



Climatic conditions are favorable to the growth of subtropical and 

 warm temperate vegetation. Frost is nearly but not quite impossible; 



* L. V. Pirsson and T. Wavland Vaughan, Amer. Jour. Sci. 36: 70, 71. 

 1913. 



t Bull. r. S. Nat. Mus. 25: 40. 



