Well in the top right corner is the date "Aug 29.68" when I zoom up
the screen in Mozilla Firefox with the Image Zoom 0.1.7 extension. I
can't imagine an 1868 date though in Montgomery, NY they are trying to
get the "US first scientific expedition" on the National Register of
Historic Places (a state roadside marker there) where in 1793 a farmer
digging in "marl" above the clay and below the peat, a good
fertilizer, found at 8 feet the remains of a strange animal's bones, a
mastodon. Around 1800, Peale, the famous portrait painter of American
notables (Washington comes to mind) excavated the full skeleton of the
mastodon. In a news article I just read in the flood ravaged area in
New York State at lunch, (nearby Myers Grove, NY had 53 house
condemned for safety and the Government doesn't buy mortgages) it
stated also that President Thomas Jefferson asked Lewis and Clarke to
bring back a mastodon "dead or alive" as he was fond of their size,
showing a piece of it there to counter a prevailing rumour in Europe
that horses grazing in the New World became smaller. Also, the
mastodon showed, almost a heresy, that God would allow his creatures
to become extinct. I hope they can get the site across from the middle
school on the National Register and help for the communities there
struck by flood.

As far as the painting goes, the writing strikes me, the cursive style
as modern, and not from the styles of the 19th century, but that''s
also kind of subjective.