Marcus died in his sleep at his home in New Hope, family members said.
He was a pioneer of the jazz fusion movement of the late 1960s, a musical movement that combined elements of rock 'n' roll and jazz.
Marcus had been touring lately with the quintet Steve Smith and Buddy's Buddies," a tribute band to the music of Buddy Rich, said fellow saxophonist Andy Fusco, a member of the group.
Several of Marcus' recordings have been recently reissued, including The Count's Rock Band," and Tomorrow Never Knows," which garnered five stars from Down Beat when it was released, Fusco said.
-- Associated Press