A. E. Verrill — The Bermuda Islands. 485 



The great star-coral, with star-shaped calicles about one-quarter or 

 one-third of an inch across ( Orbicella cavernosa), forms large solid 

 hemispheres, but it only lives on the outer reefs. The smaller kind 

 (0. annularis), with calicles about one-eight of an inch across, is also 

 found chiefly on the outer reefs, but is more common. The Sider- 

 astraia radians, which has crowded, shallow, confluent stars, about 

 one-eighth of an inch across, is very abundant both in shallow water 

 and on the reefs. It grows in solid, heavy, rounded masses up to a 

 foot or more across. Porites astreoides forms irregular rounded 

 and tubercular masses, up to two feet in diameter, covered with 

 minute stars, about y 1 ^- of an inch or less in diameter. It is usually 

 dark yellowish brown when living. (See Part V.) 



At the western end of the group the reefs cover a very extensive 

 semicircular area, extending 7 to 9 miles from land, with a perfect 

 labyrinth of broken and detached reefs, but more continuous toward 

 their outer margins. This reef area is larger than all the dry land. 





Figure 28. — Wreck Hill, as seen from the Sea, bearing N. % East ; after 



Findlav. 



Among the most dangerous of these reefs are the Chub Heads, 

 which lie 9 miles from the shore at Wreck Hill ; Long Bar, of which 

 the south part is 6 miles W.S.W. from Gibb's Hill Light ; and 

 Southwest Breaker, on which the sea always breaks, and which lies 

 l£ miles from the shore, and about south from Wreck Hill, which is 

 a rather conical high hill, standing detached from the other hills, at 

 the extreme western end of the main island. When seen from the 

 sea it appears dark colored. From the southwest it appears flat- 

 tened at the top, but from the south it is conical. It is usually the 

 first land made in approaching the islands from the westward. (Fig. 

 28.) The modern sand-dunes in the region of Elbow Bay, East of 

 Gibb's Hill Light, are conspicuous at sea, from a long distance, by 

 reason of their white color, and are called the Sand Hills. 



