420 grains 900 fine seated liberty trade dollars?

Hello,

I have a Trade Dollar coin from 1798 with a seated liberty holding an olive branch twoards the West with 13 stars on one side and on the other an eagle holding 3 arrows and an olive branch in his claws. it is marked "420 GRAINS 900 FINE" with a "S" above the "D" in "Trade Dollar". I looked online to source this coin but I could not find any info on it. I only see information about trade dollar coins from 18XX and not 1798. i will attach pics in a few. thanks!

i would like to know it's price because i would like to sail it. if anybody haves any information please send me an e-mail... marksingle1@hotmail.com. regards. Mark