30 THE GEOLOGY OF BERMUDA. 
great measure washed out by rains from the “red earth.” The follow- 
ing interesting passage is quoted from the letter above mentioned: “TI 
think it most probable.that in the far past there would be a great quan- 
tity of this sand on the shores of the then Bermuda. This, however, 
as the island sank, and the coral grew, would become less and less 
in proportion to the coral sand. Some of it would, one may be sure, 
always be carried up by the wind along with the coral sand, and these 
grains would accumulate in the ‘red earth,’ which one must regard as 
the residue after the removal of the calcareous matter. In this way, 
much of this voleanic sand may have belonged to the original Bermuda. 
Much of it, I cannot but think, has been carried to the island by pum- 
ice stone. Volcanic and other dust carried by the winds will doubtless 
have contributed to the mineral particles we now find in the rock of 
Bermuda.” The considerable abundance of menaccanite, magnetite, 
augite, olivine, and other volcanic minerals in the sands at various lo- 
calities may be due to the fact that the material has been repeatedly 
worked over—now blown up in sand-dunes, now washed down to the 
shores by the rains. Thus the comparatively insoluble grains would 
be concentrated and reconcentrated by the removal of the more soluble 
ealcium carbonate. Whether these volcanic grains are in part indigen- 
ous, as Mr.,Murray supposes, or have all been transported to the island 
in the form of pumice or otherwise, we might reasonably expect that 
they would now occur here and there in considerable abundance as the 
result of this process of concentration. 
Nelson reports the occurrence of ‘“‘small pieces of oxide of iron, of 
very questionable origin; menaccanite, found near the ferry between 
St. George’s Island and Bermuda or Main Island; arragonite; and a 
minute quantity of manganese in the red earth.” * Among the nodules 
of oxide of iron I have recognized both hematite and limonite. J. Mat- 
thew Jones has noticed the occasional occurrence of pieces of trap, 
doubtless brought among the roots of drifted trees.t George W. Hawes, 
Ph. D., late of the United States National Museum, has noticed the 
occurrence of pebbles of a variety of kinds of rocks. In a letter to me, a 
few weeks before his death, he wrote concerning them as follows: “One 
is a beautiful augite porphyry with large crystals finely formed of augite, 
and most of them are eruptive rocks; but I have two that are plainly 
silicious, apparently metamorphic rocks. I have found two quartz (flint) 
pebbles, small in size, and one I took out of the inside of a sponge.” 
* Op. cit., p. 105. t Geological Features of the Bermudas, p. 22. 
