This might be worth a read,
http://www.amazon.com/The-Measure-Manhattan-Cartographer-ebook/dp/B007Q6XMT2
Renowned for his inventiveness as well as for his bombast and irascibility
Nice to know that surveyors haven't changed any in the last 140 years!! 😛
***Moderator, please move this to "Surveying"***
While I did not attend last winter's NYSAPLS conference, I understand there was a presentation given about finding the original bolts set by Randel.
Of course, the only place where there is any possibility of finding said bolts is Central Park, where the street grid was originally laid out, but then suspended from 59th Street to 110th Street and from Fifth Avenue to Eighth Avenue.
Even that is tricky, because much of Central Park, although it looks natural, was landscaped during it's construction, from 1857 to 1873.
My understanding from years ago was that there was only one original bolt left (set in lead poured in a rock just north of the Dairy and the 65th Street Transverse Road off the Central Drive), but the site below seems to indicate that several others may exist.
http://prezi.com/y4wr1mya0ulr/nysapls13/