484 A. E. Verrill — The Bermuda Islands. 



and often broken up into distinct patches or groups, and small 

 detached heads, with deep and narrow channels between them. 

 These broad nearly level reefs are locally called " Flats." (Fig. 27.) 



The four North Rocks, which stand on the platform of the outer 

 reefs, about 8 miles north of St. George's Island, are the only points 

 that are exposed at high tide. The largest of these is only about 12 

 or 13 feet high, above low tide, and about 7 feet in diameter (see 

 figure 30). They are, like the reefs themselves, last remnants of 

 what were once islands, now destroyed b} r the sea. (See map, fig. 26.) 



These rocks are interesting historically, as well as geologically, for 

 it was in close proximity to these that the " Bonaventura," with 

 Henry May on board, was wrecked in 1593, as mentioned on another 

 page, and so they were represented, with this wrecked vessel, on the 

 reverse of the original seal of the Bermuda Company (see figure 29, 

 ch. 23). They lie 12 miles N.N.W. from Catherine Point, at the 

 eastern end of St. George's Island. Mills Breaker, which is dry at 

 low water, lies 6 miles N.E. from Catherine Point. (See map, fig. 

 26.) 



Within the outer reefs, and between the anchorages, there are 

 innumerable detached reefs and groups of reefs of various sizes and 

 shapes, but often covering many square miles, where the water is so 

 obstructed and filled with reefs that no vessels of any kind can pass 

 through them, except small boats in pleasant weather. 



All these reefs are overgrown with corals of various kinds, sea-fans, 

 serpulae, mussels, sea-w r eeds, corallines, nullipores, and many other 

 living organisms, which greatly protect them from the wear of the 

 waves, and on the outer parts raise the level considerably above that 

 of the underlying limestone rock. Were it not for this protective 

 covering the reefs would be speedily worn away and destroyed. 



Among the reef-corals that are most efficient, both in protecting 

 and building tip the surfaces of the reefs, are the " brain-corals " 

 (Mmandra), the "star-corals" (Orbicella and Siderastrcea); Porites • 

 and the finger-coral (3flllepora alcicoriiis). The latter is very 

 abundant on all the reefs and rocks, including those near the shores, 

 for it grows in very shallow water. It forms large and handsome 

 masses of elegantly branched fronds, dark russet-brown in color 

 when living. The common brain-coral (31. labyrinthiformis) is 

 exceedingly abundant, and forms thick, rounded masses, sometimes 

 4 or 5 feet in diameter, orange yellow in life. The other brain-coral 

 (3f. cerebrum) forms similar masses, usually light yellow or greenish 

 in color, chiefly on the outer reefs. (See Part V, and plates.) 



