This Santa Claus woodcut was by famous Morro Bay artist Charles Hoxsey "Robby" Robinson (1862-145) who had studied from approximately mid 1890s to 1904 at the St. Louis School of Fine Arts at Washington University (same place where Paulus Roetter had taught).  His mentors there were John Hemming Fry (1852-1946), Carl Friedrich von Saltza (1858-1905), and Edmund Henry Wuerpel (1866-1958).  This postcard was dated 24 December 1940 and was sent to my grandfather-in-law, architect Alastair Simpson (1910-1992), who had apparently studied watercolor with him.
 
The text below the woodcut says: "Just a rough cut Santa to let you know I am thinking of you too this Xmas tide.  Uncle Robby."