When I saw this cover on eBay
, I clicked the BIN before anyone started bidding on it. There are no postal marking on the reverse.
While it appears to be an ordinary cover with a transit marking, it is in fact MISSENT and unmarked as such as per Post Office regulations:
Postal Laws and Regulations.
XIV. MISSENT, NIXES, AND MISDIRECTED MATTER.
(a.) Missent Matter.
406. Missent matter, that is, plainly directed matter sent in the wrong direction by the act of postal officials, should, as soon as discovered, be placed in the first mail going in the proper direction.
407. Missent matter of any class, received at any post office, must be stamped "Missent," and postmarked with the date of receipt before the same is forwarded to its proper destination.
Cloverdale is very near the northern border of Sonoma County, 32 miles south of Ukiah, Covolo is 64 miles north of Ukiah.
I have marked the towns in red on this 1904 map of Mendocino County. The small red mark just north of Cloverdale is Preston, it was then Preston Colony during the 1870-80s and became a town in 1890, complete with post office.
The Covolo postmark helps identify the year as Men 810 EKU was Nov 17 1883 and the LKU was Dec 9 1884. It does seem odd that the Covolo pm reconciled the indicia but neglected to mark the cover missent.