On other stamps of the sheet:

34 (c.) - Etienne Brule (1592-1633), First European to see the Great Lakes, 1610;
34 (c.) - Pierre Esprit Radisson (1636-1710) and Medard Chouart des Groseilliers (1625-1698), British expedition to Hudson Bay, 1668;
34 (c.) - Recollet wilderness mission, 1615.

Father Jacques Marquette S.J. sometimes known as Père Marquette, was a French Jesuit missionary and explorer of North America who founded Michigan's first European settlement, Sault Ste. Marie, and later founded St. Ignace, Michigan. Jacques Marquette was born in Laon of the Aisne department in Picardy in northern France, on June 10, 1637 and died somewhere near the Lake Michigan on May 18, 1675.

Louis Jolliet also known as Louis Joliet, was a French Canadian explorer, hydrographer and merchant of fur known for his discoveries in North America. Jolliet was born in a French settlement near Quebec City on September 21, 1645 and was presumed to have died in 1700.
In 1673 Father Marquette and Louis Jolliet were the first Europeans to see and map the northern portion of the Mississippi River.