194 
Records of the Geological Survey of India. 
\yoh. XI. 
the mud away from the surface, leaving a superficial layer of fragments behind, 
which thus have the appearance of constituting the whole mass. On digging 
down a foot, or less, the true composition becomes apparent. There are often 
cracks, also, which show the mud below, sometimes in a dried, in other cases in 
a still pasty condition. In the centre of one of the Kyauk Phyu mounds there 
was a circular space, about 10 yards diameter, where the surface crust, composed 
of fragments cemented by dried mud, was not more than 9 inches thick, and was 
intersected by numerous shrinkage cracks through which a ten-foot stick could 
easily be thrust into the soft mud beneath. The highest part of the mounds is 
generally at or near the centre, but not always. One of the large mounds south¬ 
east of Pagoda Hill has its summit about halfway between the centre and 
circumference. Scattered over the mounds, more commonly towards the central 
part, but sometimes at or near the edge, there are generally a few mud cones from 
a few inches to as many feet in height, with craters at the top containing more or 
less liquid mud. To these I shall allude again. 
The mounds, which are quite bare of vegetation themselves, are surrounded 
by a ring, varying in breadth, but averaging perhaps 60 to 100 yards, of casua- 
rinas, not very thickly grouped, and unaccompanied by any other trees. Beneath 
them is thinly scattered grass. Immediately outside this ring the ordinary 
jungle commences. Casuarinas arc only found in the islands along the sea coast 
and around the volcanoes. They prefer a saline soil, which they obtain in both 
positions. The mud ejected from the volcanoes is invariably saline, and while 
favouring the growth of casuarinas, prevents that of ordinary jungle. At the 
two large salses south-east of Pagoda Hill (and in this case only, as far as my 
experience goes) ^he casuarina ring is replaced by one of phoenix palms. 
The most perfect examples I have seen of the conical form of volcano are 
the two salses at Kyauk Phyu nearest the sea. One of these is about 40 feet 
high from the inner side of the casuarina ring,* with a slope increasing in steep¬ 
ness towards the top) of the cone, where there is a crater 12 feet in diameter, filled, 
(at the time of my visit), to within 4 feet of the top, with thickish mud into which 
a stick 10 feet long could easily be thrust. The other cone is similar, but smaller. 
Mounds are commoner than well developed cones. The former would apjiear 
to be in an earlier stage of development. The difference in form is partly 
caused, also, by the mud ejections in the former case shifting their positions at 
different times to difl'erent piortions of the mound. Thus at one of the salses 
south-east of Pagoda Hill, the largest mud craters at present, one of which is 
10 feet high, are situated close to the edge of the mound. When such a change 
of position takes place, the deserted craters, which have not had time to attain 
any very large dimensions, are washed down by rain into the general mass of the 
' Owing to tte wcatliored, bi’oken up, condition of the sliHle and sandstone in the low broad 
ridge on which the volcanoes are situated, it is rather difficult to distinguish the de'bris of the 
former from that ejected from the volcanoes, or to determine how far the ridge has been produced 
by the latter. The summit of the last mentioned cone is 200 or 300 feet above the sea. 
(.'aptain Halstcd says that the volcanoes in Cheduba vary from 100 to 1,000 feet above the sea 
level. These elevations, however, include those of the billy ground on which many of the volcanoes 
are situated. 
