Extremely old Gold Coins from Bengal. Help me validate these.

I bought these gold coins from a farmer in a very remote part of West Bengal, India. I got it tested at different locations and its certainly 23 carat gold. It is 2.25gm in weight. 
However, I was unable to figure out its origin, which era it belongs to, which language is this(or what's written on it), and its possible valuation. 
Attaching the pictures below. Please help me validate this coin.

Welcome to numista.

It disturbs me that the coin is perfectly round!

I hope you did not pay much money, it's not a coin but one of dozens of  similar items with meaningless gibberish that keep appearing