300 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1926 
The gems then have their origin in the ancient Archean rocks, but 
in just which members of the series they took their birth is not as yet 
known with certainty, except in the case of a few species. 
While gems are found in many parts of the area, it is the streams 
flowing through the Balangoda, Rackwana, and etieue districts 
that afford the chief supplies a precious ‘stones. These three dis- 
tricts lie near one another in a relatively small area in the central 
part of southern Ceylon, halfway between the city of Kandy and the 
southern shore of the island. 
The Ratnapura district is of especial interest, and much attention 
has been directed to it in recent years. Ratnapura signifies in Sin- 
ghalese ‘“ City of Gems,” and the little town which gives its name to 
the district is situated in the midst of the most exquisite scenery in 
Ceylon. It lies in a wide depression surrounded by hills 800 to 
3,000 feet in height, the whole clothed with w onderfully beautiful, 
intencoly, green tr Fe vegetation. The finest views of Adam’s 
Peak are staan from here, and the outlines of the hills and moun- 
tains, resulting from age-long secular decay acting on the folded 
and jointed system of ancient gneisses, gives the hills and mountains 
sharper outlines than those presented by the rocks of corresponding 
age in our glaciated regions of the northern world. The slopes when 
not washed bare, as they are in places, are mantled with red residual 
soil or “cabok.” Apart from its tropical features, the landscape 
must present a picture similar to that which was displayed by the 
Laurentian Plateau of Canada in pre-glacial times. Everywhere 
along the bottomlands which border the streams and little rivers 
flowing through the Ratnapura Valley are paddy fields, the fertile 
mud yielding under native cultivation rich crops of rice. 
Much attention has recently been directed to the gem fields at 
Palmadulla, about 12 miles in a southwesterly direction from the 
town of Ratnapura, on account of a remarkable “find” made there 
a couple of years ago, sapphires and other gems to a value of some 
9 lakhs of rupees ($297,000) having been taken from an area of 
between 3 and 4 acres in extent in a certain paddy field. These 
included some very large fragments of excellent blue sapphire 1 and 2 
pounds in weight, as well as fine yellow sapphires and other less 
valuable stones. (PI. 2.) 
The Palmadulla workings are situated in a large stretch of paddy 
field in the bottom of the valley here. which has been cultivated for 
rice over a period of perhaps 1,000 years. The paddy field is under- 
lain by clay, which is from 10 to 20 feet thick. Immediately beneath 
this there is a bed or layer of gravel called by the Singhalese “ illam,” 
which is usually thin and which in its turn rests on the decomposing 
surface of the country rock. The gems, if present, as is the case in 
all the Ceylonese gem deposits, are found in the illam, which thus 
