Great evening hunt, LC and an old silver that I need an ID on please

[Wallhangers]

What a night! It is not easy getting old coins in Michigan but tonight I got lucky. Got my first LC of the year and my oldest, 1846. Soon after that, I dug what I thought was a worn smooth seated dime but didn't look at it good until I got home. Please help me ID exactly what coin this is, I believe the date is 1785 or 17??. The pics aren't showing up very good for you to see the date. This coin is the same diameter of a dime but much thinner and a little beat up. Never thought I would break into the 1700's in Michigan. Also found some nice buttons and other relics. Everything on this site that I dug appears to be from the 1800's, including this part of a gun. Thanks for looking.

 

[Roger Mn.]

You got a great spot there and nice finds.
Do you think that cantab thing might have held the saddle on.

 

[zaxfire69]

I clearly see a 17 on the date. Can't make the rest out.