James Henry Madsen

James "Jim" Henry Madsen Jr.
Born28 July 1932
Died28 November 2009(2009-11-28) (aged 77)
Salt Lake City, Utah
NationalityAmerican
Alma materUniversity of Utah
Known forpaleontology, Allosaurus, Ceratosaurus
Parent(s)James Henry Madsen Sr., Eva Anna Weidner

James "Jim" Henry Madsen Jr. (July 28, 1932 – November 28, 2009) was an American vertebrate paleontologist and geologist and main leader of excavations at the Cleveland-Lloyd Dinosaur Quarry in the 1960s. Madsen primarily worked to describe skeletons of Allosaurus from the quarry, eventually getting the site to become a National Natural Landmark in 1965 and a national monument after his death.