312 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1926 
The little town of Mogok is situated on the valley floor, the pop- 
ulation consisting of Burmese, Chinese, Shans, and some Indian 
Tamils. All look well and happy, requiring a very small income 
for their support and being apparently tolerably contented with 
what they have. Lines of sturdy, well-cared-for pack ponies with 
their quaintly clad drivers come over the hill trails from the Shan 
northern States and from China with loads of rice or other merchan- 
dise, and on market days the bazaars present a scene which, for 
color, movement, and picturesqueness of costume, can hardly be 
surpassed anywhere. These bazaars contain, even in this remote 
corner of the Far East, a large variety of western goods, as well as 
all manner of native products. The Burmese women, who carry on 
most of the retail trade of the country, usually wear skirts and jack- 
ets of very bright but well-matched colors, often of silk, with a 
large piece of some bright-colored fabric folded about the head, 
giving them a very graceful and picturesque appearance. Bath 
towels of western manufacture are now often used as a head cover- 
ing in Burma or are worn thrown about the shoulders. Gems and 
native silverware are very generally offered for sale. 
The rocks in the Mogok region are everywhere covered by a mantle 
of residual soil produced by the secular weathering. This seems to 
be heavier than in Ceylon. It is almost impossible to obtain speci- 
mens of the fresh rock except by blasting. Where good cuts have 
been made the rock is seen to have been bleached and kaolinized, 
while this kaolinized product is in its turn overlaid by a thick 
covering of red clay, which in some places approaches laterite in 
appearance, although it is less compact. This red clay, which also 
overlies the limestones, is remarkable for the manner in which it 
retains its form and even the tool marks upon it when cut into 
vertical walls or into steps running down steep declivities. Not- 
withstanding this fact, large quantities of the residual clay are 
washed down to the lower level by the heavy tropical rains, where 
it mingles with that formed by the weathering and solution of the 
rocks in the valleys, and in some places is subjected to further 
transportation by the action of streams running down the valleys, 
especially during the rains. Thus the residual soils pass into alluvial 
deposits. 
There are three distinct ruby bearing areas in Upper Burma— 
those of Mandalay, Mytkynia, and the district about Mogok (includ- 
ing Kathe). The latter is by far the most important and constitutes 
the principal ruby producing tract in the world. Other areas will 
undoubtedly be discovered in the valleys of Upper Burma as time 
goes on; in fact, when the writer was going up the Irrawaddy, in the 
month of February, 1925, a party of gayly clad prospectors left the 
boat at Dundan, about 25 miles north of Thabeikkyin, a boom being 
