The immigration record of Ona Kedenytė says she is going to her brother in law, Vincas Swilpas. See https://www.familysearch.org/ark:/61903/3:1:33SQ-GP1H-DH? line 13. The correct name in Lithuanian is Švilpas. It seems likely that this was Mary Shellpak's original family name, and therefore she would have been Švi̇lpaitė.
I sent you another note after more investigating. Mary's family was not Lithuanian, so I was wrong. It seemed like a good possibility! These people intermarried like rabbits. ;)
I was trying to find more info on Vincas Švilpas but I haven't found him on any census yet.