Jensen extrapolates that the creature was a 50-to 60-foot-tall, 80-ton vegetarian of the Brachiosaurid family, which lived 140 million years ago. He calls it "Ultrasaurus," big brother of "Supersaurus," whose eight-foot scapula he found in the same area in 1972.
"Dinosaur Jim" to his profession, Jensen has also discovered the world's largest dinosaur skull (in northern Montana), what is possibly the world's oldest bird (found in the same Delta, Colo. site) and a creature with teeth like a mammal but skull structure like a reptile that might be the missing link between the two (found in Argentina with a Harvard expedition in 1964). Ten years ago in Antarctica, Jensen chipped from a cliff the skull of Lystrosaurus, a 200-million-year-old mammal-like reptile that has been called (by geologist Laurence Gould) "one of the truly great fossil finds of all time." The very existence in Antarctica of Lystrosaurus, an animal that lived in Africa and Asia too, appears to prove that those three continents were once joined.
Finds like these inspire researchers in different fields. "The main significance of Ultrasaurus," Jensen observes, "is that it may eventually help scientists learn what kind of heart these animals had that could pump blood that high off the ground."
Jensen has dreamed about dinosaurs since his Mormon childhood on a farm in Utah. Bored with high school, he flunked chemistry and dropped out. The University of Utah let him take geology without a high school diploma, and Jensen liked the subject. But he flunked chemistry there too, and decided to see the world before trying any more schools.
He bummed his way through 38 states, worked on a railroad crew and finally wound up in Alaska as a longshoreman. There he married Marie Merrell in 1941 and had two sons. Jensen went through more odd jobs and two failed businesses in Hawaii, Washington and Utah before returning to Alaska in 1948, where he and his family lived mostly off the land. In 1955 he landed a job on the technical staff of the Harvard University Museum of Comparative Zoology, thanks to a friend's recommendation, and designed highly praised exhibits in paleontology. (He's a skilled artist whose paintings now hang in the Anchorage Historical and Fine Arts Museum, among other places.)
Brigham Young lured him home in 1961; yet the school has never allowed him to teach formal courses. "If one doesn't have the appropriate degree," he grouses, "you're looked at as though you're a janitor." Actually, things are not that bad; in 1971 the University awarded Jensen an honorary doctorate in science. He never did pass chemistry though.
Dinosaurs are not just something imaginary, like a space vehicle whizzing past Mars," Jim Jensen exclaims. "In today's plastic world, dinosaurs are real." They would be especially so to anyone who has 100 tons or so of dinosaur bones lying around his work area, as Jensen does. A 61-year-old paleontologist with every professional credential except a degree, he was digging in an ancient river bed near Delta, Colo. last summer when he came across an 8'10" scapula, or shoulder blade. There is increasing evidence that the bone may have come from the largest dinosaur ever found. "It's hard to tell the size of a car from a hubcap," says Jensen, who heads the two-man staff of the Vertebrae Paleontology Research Laboratory of Brigham Young University at Provo, Utah. "But I'd say the animal's leg bones must have been 20 feet tall."