'Rosetts stone' has been found for the undeciphered script, the so-
called 'indus script'. Treating the script as a composition of
hieroglyphs with the underlying language, mleccha, the code has been
unraveled. The Rosetta stone is the Sohgaura Copper Plate
Inscription which contains both Sarasvati hieroglyphs and brahmi
syllabic script.

http://s1.amazon.com/exec/varzea/ts/exchange-
glance/Y01Y2082414Y0848505/002-5207429-3881666

I have worked in this set of 7 books very elaborately on the
Sarasvati hieroglyphs (so called signs and pictorial motifs of the
so-called indus script). Each glyph is read rebus (with sound-alike
homonym words) connoting metals, minerals and furnaces used by
artisan guilds. Yes, for all 400+ signs and for 100+ pictorial
motifs of the corpus of epigraphs.

homa bison (Pe.); hama id. (Mand..); soma a wild buffalo = bison
(Kui); homma bison (Kuwi); ho_ma sambar (Kuwi)(DEDR 2849).
http://www.hindunet.org/saraswati/Indian%20Lexicon/buffalo.htm
So, when a bison is shown on seals etc. it connotes homa 'bison';
read rebus with the homonym hom 'gold' which is cognate with
soma 'electrum' (Rigveda).

Some Sarasvati hieroglyphs are also used on copper plate
inscriptions of pre-historical periods, as in Sohgaura copper plate.
These hieroglyphs are also similarly read. See
http://www.hindunet.org/saraswati/bhairava1.doc

A continuation of the note on Bhairava, s'ankha and maritime
tradition. Please browse this URL document. Appended to this
monograph is a reading of the first line of Sohgaura Copper Plate
Inscription composed mostly of Sarasvati hieroglyphs.

The line relates to the facilities (together with a pair of
kos.t.ha_ga_ra, storehouses) provided to itinerant metalsmiths of
artisan guilds at the junction of three highways.