As I have once before mentioned, this wave broke in many places over the reef and scattered some of its spray into the lagoon, but in most places the reef was sufficiently broad and elevated to receive and check its entire force.

In many places the coral rocks were covered with vegetation,--the beginning, as it appeared to us, of future islands.

Thus, on this reef, we came to perceive how most of the small islands of those seas are formed.

On one part we saw the spray of the breaker washing over the rocks, and millions of little, active, busy creatures continuing the work of building up this living rampart.

At another place, which was just a little too high for the waves to wash over it, the coral insects were all dead; for we found that they never did their work above water.