A. E. Verrill — The Bermuda Islands. 



4 S3 



differing in fineness and in the amount of small shells and shell-sand. 

 It was not very profitable dredging, but the siftings yielded many 

 small undescribed shells, annelids, etc. 



On such white bottoms a very large black Holothurian (JStichopus) 

 is very abundant. It becomes 15 to 18 inches long, and three or 

 four broad. Associated with it are numerous large, nearly black or 

 dark purple sea urchins (Toxopneustes). Both are conspicuous with 

 a water-glass, on account of their dark colors. (See Part V.) 



The bottoms of chalky mud make excellent anchorages, for it is 

 said that vessels never drag their anchors in it, owing to its tenacity. 

 It is related that a British sloop-of-war, the " Driver," once lost her 

 bowsprit, while weathering a northerly gale in Murray Anchorage, 

 by plunging it so deeply under water that she fouled it under her 

 anchor cable, but yet did not drag the anchor. 



12.— The Beefs or "Flats"; North Bocks. 



The outer reefs form an almost continuous semioval boundary wall 

 to the region of lagoons, for over 30 miles, from east of St. George's 

 Island all around to and beyond the western end of the group. 

 They are from half a mile to two miles or more in breadth and in 

 most places are only slightly covered by water at low tide, so that 

 the seas break heavily upon them, in long lines of white breakers in 



Figure '27. — The Eeefs or Flats near North Rock. Phot. December, 1875, by 



J. B. Heyl. 



windy weather. In many places, as in the vicinity of the North 

 Rocks, quite extensive areas of the flat reefs are laid bare by low 

 tides. In other large areas the reefs are covered by from 1 foot to 

 8 feet of water at low tide. These reefs are very irregular in form, 



