This is a good read on nails; http://www.pasttools.org/nails.htm Roland Robbins mentioned in one of the articles was known by my dad who built the little replica cabin that used to be there. He was apparently quite a character and probably worth googling for anyone interested in that project.
This is a link to Eric Sloane's article on colonial nail making; Sorry for the length of that, I was googling by a nail I remembered mention of in the article. You maybe need to cut and paste into your browser? http://books.google.com/books?id=NWE3f0IEiMQC&pg=PA92&lpg=PA92&dq=plancher+nail&source=bl&ots=aMxfkF9vRE&sig=r-RQS1fIEWsOwLRMXAAt7p0cH-I&hl=en&ei=GMW1ScSKM42INeLJgNkK&sa=X&oi=book_result&resnum=8&ct=result#PPA92,M1
This is a nail from a saddlebag cabin I tore down some time ago. I'm thinking they were in panelling but oldtimers has apparently set in. Not positive anymore.
Not sure if or whether it pertains in any way, I live on the edge of the igneous blue ridge where it meets the metamorphic valley and ridge. The old beach road about 300 million years ago. On a restoration on the blue ridge side I was dealing with nails from the first furnace in our area,Point Hope Furnace. The ore was from our side. The furnace shut down when better ore was found on Iron Ridge on the valley and ridge side. The nails are noticeably more brittle from our ore than from the later ore.