Thanks to Russ Ryle and the US Stamp Society a copy of the book "1877 New York Post Office 3rd Division (Mailing & Distribution) Annual Report" is now available for free download on Stamp Smarter here
http://stampsmarter.com/learning/Home_USPOD.htmlHandwritten with some pages that include cancellations and auxiliary marks, it also provides insight in the running of the 3rd Division NYPO.
Don