The smooth, round pebbles found in this river
are called "Bana Lingas" and also Narmada Shiva Linga. Several
scriptures extol the virtues of worshipping the Bana-Linga. What
Salagramas are to Vishnu, the bana-lingas are to Shiva - sacred and
self-manifest representations. If the Salagrama are stones found only
in the Gandaki river, the bana-lingas are stones found only in the
Narmada river. The currents of the Narmada river are very strong and
forceful, and the stones are carried from the rocky river-sides,
rendering them smooth and polished.
According to Yajnavalkya-samhita, the bana-lingas obtained in the
river Narmada are the very forms of Siva assumed by the God at the
request of Banasura and are therefore the holiest of objects.
Worshipping one bana-linga gets the benefits that can be procured by
worshipping a crore of other lingas.

The demon Bana was the eldest son of Bali, who in turn was the
grandson of Prahlad. Bana was a great devotee of Siva, and Siva gave
him his own representative in the form of a natural linga of worship
(banrchartham krtam lingam); hence the name Bana-linga. As the bana-
lingas are self-manifest forms of Siva, they are holier than any
other anionic forms of Siva. According to Yajnavalkya-samhita the
bana-lingas are actually bits of the river-side rock, which flowed
into the stream Narmada. The rock by the side of the river was itself
the linga, the form assumed by Siva to bless the asura Bana. Siva
dwells in that rock and the parts of the rock which we find in the
river are, therefore, aspects of Siva. The bana-lingas in the Narmada
River may be the shape of a ripe jambu-fruit, or of a swan's egg.
They may be honey-coloured, white, blue or emerald-hued. Suta-
samhita, which also extols the bana-lingas, mentions that the best
bana-lingas are like the lotus seeds or like the hen's egg in shape.
According to scriptures, one can simply keep them in pooja and
worship and there is no need to ceremonially instal the bana-lingas.
They do not require the normal ritual of invocation of divine
presence (avahana) etc, for the divine presence is already there, and
will continue to be there quite independently of any rituals. Its
worship is said to secure worldly welfare as well as emancipation
from worldly involvement. It is therefore claimed that the bana-linga
when worshipped is a thousand times more effective than any other
linga.