Ellery Harding Clark (March 13, 1874 – July 27, 1949) was an American track and field athlete and a writer. He was the first modern Olympic champion in high jump and long jump.Ellery Harding Clark (March 13, 1874 – July 27, 1949) was an American track and field athlete and a writer. He was the first modern Olympic champion in high jump and long jump.