CORALS AND CORAL ARCHITECTURE. 



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enlarge into the plumed tops of cocoa-nut trees, and a line of green, in- 

 terrupted at intervals, is traced along the water's surface. Approach- 

 ing still nearer, the lake and its belt of verdure are spread out before 

 the eye, and a scene of more interest can scarcely be imagined. The 

 surf, beating loud and heavy along the margin of the reef, presents a 

 strange contrast to the prospect beyond. There lie the white coral- 

 beach, the massy foliage of the grove, and its embosomed lake with its 

 tiny islets. The color of the lagoon-water is often blue as the ocean, 

 although but 10 or 20 fathoms deep, yet shades of green and yel- 

 low are intermingled." In some instances there is a ship-channel 

 through the reefs into the lagoon, in others only a shallow passage, in 

 others none at all. 



Fig. 14. 



Coral Island, or Atoll. 



By a series of soundings, we have some idea of the depth of water 

 near the ocean-side of many of the great reefs. 



Seven miles from Clermont Tonnerre, of the Panmotus group, bot- 

 tom was not found at 6,870 feet. From another point of the same isl- 

 and, only 1,500 yards from shore, the lead touched at 2,100 feet, then 

 dropped off (probably from a projecting coral), and descended 3,600 

 feet without finding bottom. In another instance, about a cable's 

 length from the island of Ahii (Peacock Island), in the same group, 

 the lead struck at 900 feet, fell off and touched bottom at 1,800 feet. 

 Off Whitsunday, 500 feet from the shore, no bottom was found at 1,500 

 feet. Deep soundings in the immediate vicinity of coral-islands is al- 

 most universal. Should these submerged islands of the Pacific be 

 again elevated until their gigantic coral crowns should be lifted above 

 the waves, an immense area of the Pacific would be converted again 

 into an archipelago, not indeed of verdure-covered land as before, but 

 of hills and mountains of coral-rock, bristling with crags, sublime with 

 precipices and stupendous walls. 



The great coral-bearing area of the Pacific is about 12,000,000 square 

 miles in extent, nearly as large as the continent of Africa, or of Europe 

 and North America combined. It extends from the southern side of the 

 Hawaiian Islands to Pitcairn's Island to the southeast, thence 2,000 miles 

 broad and 6,000 miles in length to the Pelew Islands, north of New 



