Dick, Weiser's quote doesn't refer to a dollar bill or a dollar coin or a dollar in the abstract.

It means a buckskin that happens to be valued - we think - at a dollar. He was addressing a council of Indians in Pennsylvania to whom he gave "wampum" - not English money:

http://tinyurl.com/ctx75t9

What's more, the only kind of "dollar" in circulation at the time was the Spanish milled dollar ("piece of eight") - not the U.S. currency, which didn't appear until 1792.

It's a long, long way from 1748 to 1856.