Professional help - I can't provide
However, as with the other cut-outs, this is a postal marking which indicates when and where from the mailed item was sent. Stanhope, NJ has a post office, which started operating in 1825 and still is active. This marking was applied to a stampless folded letter sometime after 1825, probably between the 1840's to 1850's. This is a better one to have on an intact folded letter, but is nearly valueless monetarily (but may have value for someone looking for a cancel reference).