This feature shows poorly in Rukl's atlases, but is well photographed in chart I of Cherrington's _Exploring_the_Moon_. It seems to be visible only at low sun angles; I have seen it not long after Lunar sunrise, but have not looked for it before Lunar sunset.
San Francisco Bay area observer <d _at_ timocharis.com> David North drew my attention to this valley, and stated that he had not seen any reference that called attention to it. Perhaps, in his honor, we should name it "North Valley" -- the more so because it lies to the south of Mare Crisium ... :-)
I don't suppose Dave will agree when I say it should really be "Vallis North" :-)
|Chart 37||Moon-Lite Atlas for chart 38||Chart 39|