COLONIAL(?) ID HELP PLEASE

[Yeasty]

Guys,

I bought this coin today at a flea market auction. It was among a handful of old foreign coins and a few Buffalo nickles and wheaties. I won the auction for $5.00.
From what I can perceive the obverse has a bust facing right. I think I see the nose.
The reverse has a person seated on what looks like a globe and there is a spear(?) which angles down between the seated person and the globe. The date appears to be XX98 or possibly XX99. There seems to be quite a gap between the numbers. I'm assuming that XX = 17. There is also an arc between the seated person and the date.
It weighs 11.4 grams and it's the same size as a modern half dollar.
I have researched the '09 Red Book and seen a couple of colonial types with a similar seated figures on a globe but (in my eyes) am unable to nail it down.
I have not cleaned it.
Is there a possibility that it may not be an American coin?
Any help with identification would be greatly appreciated.

Thanks
Pete

 

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[l.cutler]

1799 Great Britain penny. That is George III on the obverse and Britannia on the reverse.

 

[Yeasty]

Thanks I.c! You nailed it!
With your information I found a picture of one in MS63 condition on EBay. The BIN price is $750 which should make mine worth about a buck, if I'm lucky.
Pete