The Atlas Tales website lists a good handful of text page illustrations in the late Fifties at Timely/Atlas/Marvel attributed to Marie Severin (over twenty, but at least a few of the later ones are reprints; more, if titles were changed).
Many Atlas text pieces reused art from comics stories, but a few were original; Joe Maneely initialed some of his with an "M". Atlas Tales cites Marie Severin's first known text piece there as signed (Astonishing 54, Oct/56), but I can’t see any initials or signature on it. The site attributes only the pencils on her spot illos, but I think it's a safe bet to say that she inked herself. As an example:
These two Severin pieces of spot art, like a tree falling in the forest without being posted on YouTube, haven't yet been cited on the Internet that I can find. They're from Cartoon Kids 1, no month, 1957. Joe Maneely did the rest of the issue; he's been the best guess so far as the artist on the text piece.
Yep, the faces of the kids certainly point to the work of Marie.