Marguerite Florence Laura Jarvis, also known under the pseudonym of Oliver Sandys (October 7, 1886 – March 10, 1964) was a British writer, screenwriter, and actress. She used several other names and aliases, such as Countess Barcynska, Hélène Barcynska, Marguerite Florence Barclay, Mrs. Armiger Barczinsky, Caradoc Evans Marguerite, Marguerite Evans, Armiger Barclay, and Marguerite Barclay.