:;atural areas and regions 



707 



VIRGIN GORDA 



The cretaceous mountain axis ter- 

 minates eastward in the hills of Virgin 

 Gorda. Tlais island lies a few miles east 

 of Tortola and is but sparsely inhabited. 

 The hills along its northern coast are 

 similar to those of Tortola, St. Jan and 

 St. Thomas and they are more forested 

 and less disturbed. The lower part of 

 Virgin Gorda is largely composed of 

 great masses of coarse granite rocks, 

 forming rectangular blocks as large as 

 houses, giving one the impression from 

 the sea of a ruined city; a contiguous 

 islet of the same structure is known 

 indeed as "Broken Jerusalem." This 

 physiographic feature is very striking 

 and unusual. 



ANEGADA 



Anegada is about ten mi. long and a 

 little over two mi. wide at about the 

 middle. It rises only a few feet above 

 the sea; the eastern and central parts 

 are a nearly level plain of aeolian lime- 

 stone; the western part is a plain of 

 sand, with saline areas and salt ponds. 

 Its vegetation includes a number of 

 species not known to grow on other 

 Virgin Islands. 



REFERENCES (N. L, B.) 



Borgesen, F. The Marine Algae of the 

 Danish West Indies. Vol. 1, pp. 226, 

 fig. 1-170 (Copenhagen, 1913, 1914); 

 Vol. 2, pp. 498, fig. 1-435 (Copen- 

 hagen, 1915-1920). 



Borgesen, F., and Paulsen, Ove. Om 

 Vegetationen paa de Dansk-Ves- 

 tindiske Oer. Bot. Tidsskr., Vol. 22, 

 pp. 1-114 (1898). 



Britton, N. L. The Flora of the Ameri- 

 can Virgin Islands. Mem. Brooklyn 

 Bot. Card., Vol.1, pp. 19-117 (1918). 



Britton, N. L. The Vegetation of Ane- 

 gada. Mem. N. Y. Bot. Card., Vol. 

 6, pp. 565-580 (1916). 



Eggers, H. F. A. Flora of St. Croix and 

 the Virgin Islands, West Indies. 

 Bull. U. S. Nat. Mus., No. 13, pp. 

 133 (1879). 



Millspaugh, C. F. Flora of the Island of 

 St. Croix. Field Mus. Bot. Vol. 1, 

 pp. 441-546 (1902). 



Seaver, Fred J. The Fungous Flora of 

 St. Thomas. Mycologia, Vol. 16, 

 pp. 1-15. 1924. 



Seaver, Fred J. The Fungous Flora of 

 St. Croix. Mycologia, Vol. 17, pp. 

 1-18. 1925. 



7. DUTCH WEST INDIES 



By H. Burrington Baker 



I. general conditions 



Topography 



The five islands of this group, Curagao, 

 Klein-Curagao, Bonaire, Klein-Bonaire, 

 and Aruba lie just off the north coast 

 of Venezuela, but all of them except the 

 last are separated from the mainland 

 by great depths (1400 meters) of water. 

 Physiographically, these islands are 

 very similar to the coastal strip of 

 Venezuela, although the soil is more 

 calcareous, due to the large exposures 

 of coral-reef limestone. 



Superficially, each of these islands is a 

 canoe-anticline, with the thick, late 

 Tertiary, coral-formations at the sur- 

 face. Erosion has removed the crest 

 of the fold, so that the central region 

 exposes the older, metamorphic and 

 igneous rocks, while the narrowed 

 limestone rim is broken into bold, 

 triangular monadnocks, often separated 

 from each other by narrow-mouthed 

 bays (sunken stream valleys), and with 

 precipitous escarpments on their eastern 

 sides. 



Climate 



These islands are very arid; the 

 mean annual precipitation at Willems- 

 tad, Curagao, is 561 mm.; at Oranjestad, 

 Aruba, 435 mm.; at Kralendijk, Bonaire, 

 516 mm. The driest month is May with 

 a mean precipitation, at Willemstad, 

 of 11 mm., while the wettest is No- 

 vember, with a mean of 118 mm. How- 

 ever, the rainfall is very variable; a 

 rainy month may record precipitation 

 much greater than that of a dry year, 

 and a goodly proportion arrives in a 

 few, torrential storms. The eastern 

 sides of the islands are more arid than 

 the western ones; the desiccating trades, 

 where they first touch land, produce a 

 landscape that resembles that of moun- 

 tain peaks, at and above timberline, 

 but with occasional dunes of dazzingly 

 white, coral sand. The temperature 

 (mean annual (1903-1921) at Willemstad, 

 27°C.; extremes 20° to 33°) and the wind 



