A wonderful find for me... I have a soft spot for these oldies!
Probably dates from 1820 - 1910 which is consider the peak manufacture
and use of this type nail. According to a couple of sources, nails were
first made by blacksmiths who hammered them into shape (dating back to Roman times),
then they were cut from sheets of metal and finally by machines that tapered them
and created the flat rectangular heads.