Coat of arms of Marvel

The blazon

or, a chev. engr. betw. three leopards faces sa. — Crest, out of a ducal coronet or, a plume of feathers ar. {Borne by Andrew Marvel, the celebrated Member of Parliament, in time of Charles I. and /J.]

A blazon is the description of a coat of arms in the technical language of heraldry. The drawing comes from that text, and from nothing else.