1836.] STONES TRANSPORTED BY TREES. 461 
channels into several islets ; this fact is likewise indicated by the 
trees being younger on these portions. Under the former con- 
dition of the reef, a strong breeze, by throwing more water over 
the barrier, would tend to raise the level of the lagoon. Now 
it acts in a directly contrary manner; for the water within the 
lagoon not only is not increased by currents from the outside, 
but is itself blown outwards by the force of the wind. Hence 
it is observed, that the tide near the head of the lagoon does not 
rise so high during a strong breeze as it does when it is calm. 
This difference of level, although no doubt very small, has, I 
believe, caused the death of those coral-groves, which under the 
former and more open condition of the outer reef had attained 
the utmost possible limit of upward growth. 
A few miles north of Keeling there is another small atoll, 
the lagoon of which is nearly filled up with coral-mud. Captain 
Ross foundembedded in the conglomerate on the outer coast, a well- 
rounded fragment of greenstone, rather larger than a man’s head : 
he and the men with him were so much surprised at this, that 
they brought it away and preserved it asa curiosity. The oc- 
currence of this one stone, where every other particle cf matter 
is calcareous, certainly is very puzzling. The island has scareely 
ever been visited, nor is it probable that a ship had been wrecked 
there. From the absence of any better explanation, I came to 
* the conclusion that it must have come entangled in the roots 
of some large tree: when, however, I considered the great 
distance from the nearest land, the combination of chances against 
a stone thus being entangled, the tree washed into the sea, floated 
so far, then landed safely, and the stone finally so embedded as 
to allow of its discovery, I was almost afraid of imagining a 
means of transport apparently so improbable. It was therefore 
with great interest that I found Chamisso, the justly distin- 
guished naturalist who accompanied Kotzebue, stating that the 
inhabitants of the Radack archipelago, a group of lagoon-islands 
in the midst of the Pacific, obtained stones for sharpening their 
instruments by searching the roots of trees which are cast upon 
the beach. It will be evident that this must have happened 
several times, since laws have been established that such stones 
belong to the chief, and a punishment is inflicted on any one 
who attempts to steal them. When the isolated position of these 
