September 2, 1889.] THE TROPICAL AGRICULTURIST. 
GEMMING: CONSTITUENTS OF THE 
GRAVEL OE THE SABARAGAMUWA 
GEM REGION. 
The correspondent who has supplied us, for the 
information of our readers, with so much valuable 
and interesting information respecting the gem 
formations in and around Ratnapura, sent us re- 
cently a specimen of the gravel in which, when 
the alluvial soil is washed away, the gems, mainly 
forms of corundum, are found. Our correspondent 
hazarded the opinion that the appearance of the 
detritus afforded a proof of former glacial action 
in Ceylon. This is not so certain as that the 
water-worn appearance of the pebbles aad frag- 
ments indicate long-continued and very violent 
diluvial action, — action which, with the slower opera- 
tion of a moist, hot atmosphere, seems to .have re- 
duced rock matrices to the level of alluvium. It 
would appear to be certain that more success is 
likely to attend deep diggings in alluvial matter, 
than any search (hitherto fruitless), in the still 
disintegrated rock formations, from the breaking-up 
of which Tennent. following Gygax, had such san- 
guine expectations. Having divided the gravel 
sent to us into portions and picked out specimens 
which seemed to us the most promising, we sub- 
mitted the whole, with such guesses a3 
we were able to make, to so competent an 
authority as Mr. George Armitage. With this 
gentleman's aid we are able to indicate the main 
mineral constituents of the gem gravel : -The larger 
fragments are, as might be anticipated, qus,itz, 
intermingled with bits of graphite and of the 
ubiquitous garnet, splendid specimens of which (in 
a mineralogical sense,) were found, with equally 
fine but treacherously slippers masses of mica, in 
the imerior rocks of the Blaekwater railway slip. 
In more or less advanced stages of decomposition, 
garnets pervade large portions of the prevailing 
goeiss. But the Ceylon garnets have never 
been mistaken for rubies, as were those of South 
Australia some time ago. — The smaller fragments 
of the gravel, out of which we had picked specimens, 
which were more or less gem-like in their crystal- 
lization, consist of quartz, garnets, spinel, &o. 
Fragments more or less lustrous and of a reddish 
to dark tinge, are pronounced to be spinels. 
Some of these are pretty, but of no intrinsic 
value. They bear no resemblance to the blue spinel 
sapphires, so oommon in some of our crystalline 
lime formations. — Small, black, hard fragments, 
which, when broken, show the lustre of graphite, 
but have nothing of the soft greasiness of plumbago, 
turn out to be the very oommon mineral, menac- 
canite, or titaniferous iron. — One dark stone, which 
looked promising and whioh we fancy would look 
well if polished, turns out to be a form of spinel 
known as ceylonite, the constituents of which 
are iron and magnesia. — The only specimen of 
sapphire in the gravel is a bit of white sapphire, 
the lustre of whioh is very pure. It is probable 
that any pieces of blue sapphire which may have 
oocurred, were removed from the gravel. What 
we at first took for a fragment of blue sapphire, 
when examined by artificial light, turns out to be 
aquamarine, of whioh very large and pure speci- 
mens have been found in Ceylon, notably a fine 
speoimen in the possession of Capt. Bayley. 
Our speoimen is faintly ooloured and badly crys- 
tallized. A very pretty conglomeration of lustrous 
facets, turns out to be mica, a mineral which can 
assume numerous forms and oolours, plentiful as 
it is in our rocks, A dark, water-worn specimen 
with a resinous lustre, turns out to be opaque tour- 
maline, one of the most common pseudo-gems 
found in Ceylon diggings. A bit of rock-crystal 
is very easily distinguished from the specimen of 
25 
white sapphire, but to the uninitiated it would 
be very difficult indeed to distinguish a specimen 
which is pronounced by our authority to be the 
form of corundum known as the oriental amethyst, 
from a piece of garnet which is of a more solid 
structure than the ordinary form of, apparently, 
a number of crystals conglomerated. 
It is unfortunate that the gem gravel contains 
no specimen, at least no appreciable specimen, 
of the blue sapphire for which Ceylon is so famous. 
As for ruby, that is now too rare in the ordinary 
diggings to be expected. But the list of minerals 
in the gem-gravel is pretty extensive, as will be 
obvious when we recapitulate them, thus:— quartz ; 
rock crystal ; white sapphire ; oriental amethyst ; 
Ceylonite, and other spinels ; garnet ; aquamarine ; 
menaccanite; tourmaline; mica; graphite; with 
other mineral forms not identified. 
What is desiderated in Ceylon as in other 
countries showing appreciable mineral wealth on 
the surface, is deep digging, and systematic search 
founded on scientific knowledge of the principles 
on which earths crystallize and ores aggregate. Deep 
and thorough mining may reveal not only a 
wealth of gems hitherto unthought of, but also 
gold and other metals in appreciable and paying 
quantities. . 
THE ALLEGED COCONUT LEAF DL EASE 
(Co» municated.) 
Whether " B." in the local " Examiner " takes 
too serious a view of this matter or not, is 
a questiun to be decided by the scientists. The 
Government have done what lay in their power by 
appointing Mr. Drieberg to investigate d eport 
upon the disease, and he with the means at hi^ 
disposal has given his opinion. If, as is reported 
he has sent affected leaves to competent autho- 
rities for examination and report, I think the 
best plan is for us to wait till these reports are 
received and made public, which, no doubt, they 
will be in due time. " B." is entitled to his opinion 
as we all are to ours ; and as his intentions are 
good and praiseworthy, he ought not to be blamed 
though in his excess of zeal for the public good 
he may have over-estimated the supposed 
danger. It is well that there are amongBt us some 
wakeful and observant watchmen, for I am 
afraid too many of us are apt to slumber at 
our posts. " B." 's letters have no doubt disquieted 
the minds of many coconut owners, and therefore 
the sooner we have an authoritative verdict upon 
this question the better for us all. As for myself 
I do not think it serious, and indeed I am in- 
clined to question if there is anything in the real 
nature of disease at all ! " B." states that the 
disease is spreading, and it must be so in his 
looality. In this neighbourhood at any rate there 
is no spotting and dying of the tender fronds, and 
as for the blotching of the more mature leaves that 
is only natural in the process of decay ; that this 
is any worse now than in former years 1 do not 
believe. Attention having been drawn to the matter 
more notice is taken of it, and one is apt to think 
that here and there perhaps a few trees look as if 
they had more deoaying leaves than naturally they 
should have ; but can any one say that this has 
not always existed, and not hitherto been looked 
upon as anything unusual ? That a fungus has 
been discovered upon ooconut leaves is nothing to be 
alarmed at, for what plant is there that is not the 
host of some parasite, vegetable or insect ? When 
scientists distinctly tell us that our ooconut trees 
are the prey of a fungus, whioh attaoks the green 
fronds and, like the ool'feo leaf fungus, geeks the 
