The dome is the biggest component of a stupa and
it contains the relics, in a relic chamber, either at
the level of the basal rings at the bottom, or at the
square chamber at the top. Several shapes have
been used for the dome (Fig. 12), and some
examples are given in Table 2 and in Figs. 1 – 8.
The bell shape is the most common and next
comes the bubble shape. The paddy-heap shape,
having a gradient equal to the angle of repose, is
the most stable from a structural point of view
[Ranaweera 1998], and the ancient builders have
used this shape for the colossal stupas they built
[Silva 1982]. Domes of pot and lotus shapes are
rare and there are no existing examples of the nelli
fruit shape. The shape of the dome of some stupas
has changed from their original form during
repairs and enlargements which have taken place
at later times. For example, the Thuparama (Fig.
1) was originally constructed with a paddy-heap
shaped dome, which later took the shape of a bell.
Table 2. Architectural details of the stupas in
Table 1
Miniatures of stupas found in relic chambers give
an idea of the old form of the stupa.
The square chamber at the top of the dome was
hollow at ancient times, and even after it became
solid, its faces show railings (Fig. 10). On top of
the square chamber there are one or more
cylinders, some known as the abode of gods,
having figures of deities. The conical spire, on the
top of the cylinder is a solid, giving the impression
of a number of umbrellas put together, and at its
top rests a crystal set on a gilt minaret (Fig. 10).
Some of the small but important stupas, like the
Thuparama (Fig. 1), were found on a raised
platform with a circular plan (Fig. 13), and
enclosed within a circular structure called the
vatadage, with a roof (Fig. 14). Concentric circles
of stone pillars carried the wooden roof of the
structure, of which only some of the stone pillars
remain at present (Fig. 1).
The large stupas sprang from a square stone-paved
platform or an upper terrace raised from the
ground and bounded by a retaining wall, and
surrounded by a lower sand terrace at the ground
level, also bounded by a wall, as shown in the plan
of Abayagiri stupa (Fig. 15). Entrance gates and
stone stairs are located at cardinal points, and the