This sketch is a portrait of Paul Castelhun Trimble (1940-2021), future pressman for the San Francisco Chronicle and prominent railroad historian.  It was done in late summer or fall 1940 by artist Anna Katharine Skeele Dann (1896-1963), most likely in San Francisco.  She taught art at Monrovia High School and later founded the Pasadena School of Fine Arts (1951-1971).