Question About Unlisted Charlemont, Ma Cancel On 1888 Cover

I have this cover sent from Plainfield, MA to Goshen, MA on February 7, 1888. It also has a backstamp with a Charlemont, MA CDS, also dated February 7, 1888.

First question is, I can't find Charlemont, MA in Helbock - it appears to be unlisted. Was there actually a post office at Charlemont, MA?

Second question is, if there was a Charlemont, MA post office, why was it backstamped on this cover? It was sent from Plainfield, MA to Goshen, MA, both continuously operating from 1816 to present.

Thank you in advance for any input on these.

There are some errors and omissions in Helbock's town listings. I know of others.

Jim Forte's web page has within its post office listings: Charlemont, Franklin County, 1810-op.

Without looking at a map to see the layout of the towns and the roads/railroads connecting them, the Charlemont postmark on the reverse is likely one of two things: a transit mark from an intermediate point or a missent marking.

John Becker - thank you for the quick insights. I will definitely be checking out Jim Forte's information as another checkpoint.

I was also thinking possibly a transit marking - I will check the proximity of the towns.

That is interesting, Charlemont is the opposite direction from Plainfield as Goshen.

You're right - Charlemont is North of Plainfield, and Goshen is Southeast. Maybe John Becker was right about being missent to Charlemont! There is only the Charlemont postmark on the reverse side without any other markings, so maybe mistakenly went up to Charlemont, and then just resent to Goshen from there.