Unofficial coat of arms used by the family of John Mifflin (1661–1714) of Philadelphia.
Shield:  Or a chevron Azure.  In a sinister chief a star of 6 points Gules 
Crest:  A bird with a twig

Caution: The source contains the following warnings about authenticity:
"Readers whose chief interest is in 'authentic' arms... must look elsewhere."
—Bolton's American Armory (1927), Introduction, p. ix
"[W]e have put away all question of their right to armorial bearings. With the quaint fancies... that the bearing of officially authorized arms is a condition of nobility we are unconcerned."
—Ibid. (quoting O. Barron, 1907)
Bolton, Charles Knowles (1927)       Bolton's American Armory (2009 reprint ed.), Boston: F. W. Faxon Co., p. 115  ISBN:  978-0-8063-0044-3. .
citing Zieber, Eugene (1895)       Heraldry in America, Philadelphia: Department of Heraldry of the Bailey, Banks &amp; Biddle Company, p. 68  .
Glasshouse