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James A. Jensen

[NOTE: This article is the restored version of the one deleted from Wikipedia in 2007. It was written by Jensen's son and required substantial rewriting to remove obvious bias. This informal NOTE will be replaced by editors with standard WP notices about biographies written by family members.]

James A. Jensen (August 02, 1918 - December 14, 1998), a high-school dropout, became an internationally famous paleontologist. His extensive collecting program at BYU in the Utah-Colorado region which spanned 23 years was comparable in terms of the number of specimens collected to that of Barnum Brown during the early twentieth century. He was given the name "Dinosaur Jim" during the media coverage of his actities. Perhaps his most significant contribution to paleontology was to replace the 19th Century web of external metal struts, straps and posts that had been used to mount dinosaurs with a system of supports which were placed inside of bones, which produced free-standing skeletons with little or no obvious supports.

Life to 1956

Jensen, born (1918) in Leamington, Utah, developed an interest in dinosaurs as a child exploring the desert and mountains with his father. Unhappy with high school and the effect of the Great Depression on the farm, and with being the only working male on the unproductive farm, he left home at age 17, before graduating from high school. For 18 months, he thumbed and rode the rails through thirty states, begged, sold magazine subscriptions, logged, mined, and worked in smelters. While working in the Tooele Smelter in Tooele, Utah, he met his future wife, Marie M Merrell who lived in a now-defunct mining town of Mercur, Utah Ms. Merrell, like Jensen, came from a small farm and hadn't finished high school. Casting about for ways to begin their life, they decided to homestead in Seward, Alaska. They married in Seward in 1941, and identified the plot of land that they wished to homestead.

However, the military entered Seward in 1941, and started construction on Fort Raymond in July. The massive influx of military personnel forced most civilians to return to the Lower Forty-eight. They had two children in Salt Lake City, Utah where he went through a crash training program on the campus of the Univesrity of Utah to become a machinist and welder. He went to Hanford, WA to work on the nuclear Reactor B pile of the Manhattan Project, then went to Pearl Harbor during the reconstruction. Jensen returned to Utah where he worked at odd jobs, e.g. washing machine repairman, creamery man, truck driver, ceramics, gunsmithing, linoleum block printing, sculpting, welder, machinist, taxidermist, inventor, and writer. During this time he met Arnie Lewis who was working at the local Utah Field House of Natural History museum, mounting a large golden eagle for him. In 1951, Jensen and family returned to Seward, Alaska where he was a dock-side longshoreman for five years.

Artist and sculptor

As an artist he worked in most media. His pastel and acrylic paintings, primarily of landscapes and American Indians, are hung from Alaska to Florida. He also sculpted in stone and metal. These skills were useful in developing the new system for mounting dinosaurs.

Harvard University 1956 to 1961

Jensen was hired by Alfred Sherwood Romer at Harvard University in 1956, at the suggestion of Arnie Lewis. He was trained as a preparator in the Department of Vertebrate Paleontology in the Museum of Comparative Zoology of Peabody Museum. In addition to working on the collections and exhibits in the museum, he participated in collecting expeditions with Romer and Lewis:

Kronosaurus queenslandicus

Jensen assisted Romer and Lewis in mounting the Kronosaurus queenslandicus (1956). This was the first mount, done with Dr. Romer's support, in which the supports were concealed inside the bones. The other design element which contributed to the impression that the Kronosaurus was unsupported was to build a curved back wall that concealed all supports, which had no corners. (Romer, A. S. and A. D. Lewis. 1959. "A mounted skeleton of the giant Plesiosaur Kronosaurus". Breviora 112:1-15.)

Because of Jensen's experience in manufacturing, he was aware of techniques and materials not generally used in museum displays. While at Harvard he experimented with "rigid foam", a new industrial product, to create light-weight models. After perfecting the technique which is illustrated by the photo to the right of a cast of an Antrodemus skull, he published his findings. ("A New Casting Medium for Rigid and Flexible Molds". CURATOR, 1961, Vol.IV, Number 1, The American Museum of Natural History, N.Y.) In addition to the foam trials, he experimented with three new products for dentists. The first was the substance “alginate” which continues to be used today by dentists to take impressions of teeth. He used it in 1958 with excellent results in terms of fidelity but it deteriorated too quickly to be useful. Searching for ways to speed up the removal of matrix around bones specimens, he borrowed a Cavident and a Cavitron from dental equipment manufacturers. The first device directed ultrasonic sound waves through a tiny spatula. As it was rubbed across stone, the waves turned it to powder. The second device was essentially a small sand blaster that had to be used inside of a plexiglass box to control the dust. Neither was useful because both indiscriminately etched bone and stone.

Brigham Young University (1961 - 1984)

When he went to Brigham Young University, he helped develop the Paleontology program. He worked in the field every summer amassing a large collection of packaged bones in matrix, he continued to refine the new mounting techniques, he prepared specimens, describing some, and attempted unsuccessfully to obtain funding for an earth sciences museum. The bulk of his summer work was done in Western Colorado and Utah. In addition, he went on a second six-month expedition with Harvard University to Ichigualasto, Argentina, and went to Antarctica for three months in an expedition headed up by Ohio State University.

Exploration Method

Jensen's productive exploration method was based on two facts:

  1. he spent several months every year in the field;
  2. he visited many sites recommended by rock hounds as sources of dinosaur bones; and
  3. he used this method for 23 years.

The following list shows most of the sites he explored during the 1960s. Note that if he visited multiple sites on a single outing, they are listed here in parentheses after the date. He did not find useful material at every site, but the number of types of specimens that he found is explained by this wide-ranging exploration. Note the frequency of personal names. They usually refer to rock hounds who had notified him of the possible site.

  1. 1961 Sept 27 Powder, Washington (He was hired by BYU in June, 1961)
  2. 1961 Sept 29 Lily Park (Disappointment Draw) to look at two sauropods.
  3. 1961 Sept 30 Green River - Fish Locality.
  4. 1961 Oct 6 Soldier Summit - Insect Locality.
  5. 1961 Oct 24 Grant Lloyd Gravel Pit in Santaquin.
  6. 1961 Oct 28 Fairview, UT sink-hole collected a mastodon jaw.
  7. 1962 May 25 Spanish Fork Canyon near Spanish Fork, Utah - Fossil fish locality.
  8. 1962 Spring (Cleveland Lloyd Quarry, -To Arches National Park, -Fish quarry in the Chinle Formation, -To Montezuma Canyon near - Little Nancy Patterson Canyon , UT & Visited cliff dwellings, -Rock Shop in Green River, UT -Stopped at Capital Reef.)
  9. 1962 Summer (-Lily Park, -to Locality on the Yampa River, camping at “dinosaur draw”.)
  10. 1962 Aug/Sept Jensen/Jensen Quarry (J/62) near the Green River.
  11. 1962 Oct Third trip to Lily Park.
  12. 1963 April 2-7(Beaver Dam, UT Trip, -Rock shops in Redmond, UT, -Richfield, UT -Elsinore, UT -Speaking at the rock club meeting in Cedar City, UT -Zion National Park to Orderville, UT -To Ross Matthew Ranch in the Beaver Dam country, -Rock shop in Summit, Utah.)
  13. 1963 April 15 Hell Creek, MT project Jordan, MT Montana.
  14. 1963 May 20-23 To Last Chance area.
  15. 1963 May 25 Willow Springs of the Last Chance.
  16. 1963 July 7-16 (To south-central Ferron Mountain in North Horn Formation, -Another locality “Fast Tank Hill”, -Collected mammal teeth and jaw fragments at Dairy Springs,-To Wood Tick Point below Ferron Reservoir, -North Horn Fmtn below Flagstaff -North Horn exposures East side of Singelton Flats. -In Black Dragon Canyon -Went toward “cap” on North Horn Mountain.)
  17. 1963 July 17-23(To Bob Miller Ranch up by Hacksby, MT, -To Jordan to the 5-skull locality, -A number of localities are listed, -Paleocene Bug Creek anthill locality.)
  18. 1963 Oct 14 Last Chance Valley near Willow Springs.
  19. 1963 Oct 24-25 (To HB sites and collected plants, -To Muddy River -Down to Agate Gulch.)
  20. 1964 Jan 29-31 With James R. Jensen, went to Delta, CO.
  21. 1964 April 1 (Escalante Canyon and 4 miles down Gunnison, Utah, -Brachiosaurus locality in Potter Creek Basin, -Kelly’s Rock Shop in Mack, CO, -“The Rock Shop” in Green River, UT, -Floy Wash to show battered vertebrae material in situ, -To Musselmans rock shop in Moab, UT, -Arches National Park, UT - Price, UT regarding mount he was doing of Antrodemus for Price museum.)
  22. 1964 July 2 Willow Springs, UT area.
  23. 1964 Aug 11-22 (Grand Junction, Colorado and met with various rockhounds, -To the Brachiosaurus locality in Potter Creek Basin, -Prospected the Morrison Formation outcrops at Broughton’s fruit farm, -To John Watson’s property, -Prospected the area around Westwater, CO and the Westwater Canyon east.)
  24. 1964 Aug 24-27 (To Cottonwood Creek, UT about south of Castle Dale, Utah, To Monticello, UT BLM out at Hatch Point was just petrified wood, Dugout Ranch in Indian Creek, -To Lavender Canyon to prospect the Triassic with little results.)
  25. 1965 July 2-5 (Guided tour to Dead Horse Point State Park, Last Chance Ranch Road, -Vernal and Dinosaur National Monument.)
  26. 1965 Aug 15-17 (Moab, Armored dinosaur locality near Canyon Lands Airport.)
  27. 1965 Oct 6-8 (To Gazin lizard locality in Lower Joes Valley and South Dragon, -Prospecting; Kitchen Trail, Marys Lake Road, Cow Camp Road.)
  28. 1965 Oct 14-20 -To Quarry 20 miles NE of Moab.
  29. 1965 Nov 15-16 To a Morrison locality east of Castle Dale.
  30. 1966 Mar 21 Recon of Cad-1 locality and collected some bones.
  31. 1966 Mar 29-30 Dominguez Canyon locality.
  32. 1966 April 1 To Last Chance area west of Temple Mountain road.
  33. 1966 May 5-10 To Cad-1 locality to get it ready for geology class to dig.
  34. 1966 May 12-14 High on side of Escalante Canyon north of Delta (This site became Dry Mesa Quarry).
  35. 1966 May or June To locate Alamosaurus quarry near North Horn.
  36. 1967 April 3 (-Constructed long road to open Dominquez-Jones Quarry, Several film crews visited the site, and some geology classes.)
  37. 1967 Aug 21 Started on the Hinkle Allosaurus near the Utah-Colorado line.
  38. 1968 July Fremont River Bonebed (FRE/68) southwest of Caineville, UT.
  39. 1971 July 27 To Kaparowitz Formation off U 54 east of Henrieville, UT.

Dry Mesa Quarry

Starting in 1972, he focussed most of his work on Dry Mesa in Colorado. He worked in other locales, but the bulk of his collecting time was spent at Dry Mesa which is probably the richest dinosaur quarry discovered in North America in the second half of the 20th Century. (Updated paragraph about Dry Mesa pending.)

New dinosaurs

Following is a list of most of the new species that Jensen described. While they are generally sound, his publications reflected his lack of formal training, resulting in errors made in the assignment of sauropod material from Dry Mesa. Caveat all descriptions of Ultrasauros-Ultrasaurus-Superaurus.

Species Discoverer
Cathetosaurus lewisi Jensen, 1988
Dystylosaurus edwini Jensen, 1985
Hypsilophodon wielandi Galton & Jensen, 1979
Iguanodon ottingeri Galton & Jensen, 1979
Palaeopteryx Jensen, 1981
Supersaurus vivianae Jensen, 1985
Torvosaurus tanneri Galton & Jensen, 1979
Ultrasauros Jensen vide Olshevsky, 1991
Ultrasauros macintoshi Jensen vide Olshevsky, 1991
He did not describe all of the new species that were identified as they were collected. Additional new species will be described for Dry Mesa as they are worked out and studied at BYU.

Publications

Although he didn't complete a formal education, Jensen published starting with articles in the "Alaska Sportsman" in 1955. A list of his publications available at this link.

Legacy

Free-standing mounts

The technique for mounting free-standing dinosaurs was developed by Jensen in 1957, while participating in the mount of Kronosaurus Queenslandicus. It remains his greatest contribution to paleontology and museum display and has disseminated throughout the world.

Plastic foam casting

Jensen pioneered the use of plastic foam at Harvard to cast Antrodemus skulls as a means to reduce weight and facilitate reshaping. He published the results in 1961 as "A New Casting Medium for Use in Flexible and Rigid Molds", in CURATOR The American Museum of Natural History, Vol IV, No. 1, pp. 79-90.

Museum built around a single ramp

In the 1963-64, he designed a museum based on a novel idea: construct the entire museum around a single, continuous ramp which started at one corner on the ground floor, winding upward around each floor to the top of the building, and use this ramp as a timeline representing the evolution of life on earth. Jensen built an 8-foot long scale model and demonstrated it to administration for their approval. He mailed a ‘birth announcement’ over the names of the Dean, College of Physical and Engineering Sciences; Chairman of the Geology Department; and Jensen, Curator, Geology Department. Administrative support was withdrawn. However, the concept of a ramp was borrowed by the North American Museum of Ancient Life in nearby Lehi, Utah, without attribution, and illustrates a simplified version of the concept.

Cooperation with rock hounds

As noted above, part of his success in finding specimens was due to his interest in "rock hounds" who jointly combed thousands of square miles of ground each year. He visited them every year or so, cultivating their friendship with gifts of dinosaur bones in return for information about their latest finds.

Education

Another legacy was Jensen's interest in educating the public about dinosaurs. He enthusiastically educated the public by welcoming them into his quarries each summer. He received hundreds of letters from school kids and answered them all. In spite of the fact that BYU denied Jensen a teaching role, he encouraged graduate students to take up the profession. Today, there is a small group of graduate students who become paleontologists as a result of his efforts.

Notes

Ankle and foot versus feathers in arboreal life

Jensen collected "bird" bones in the Dry Mesa Quarry and became interested in the changes necessary for species to move from terrestrial to arboreal life. For him the sine qua non of arboreal life was not feathers. It was the ability to grasp branches, to feed and nest in trees, and to sleep on small branches for long periods of time. Feathers don't confer these advantages to the foot or ankle. He concluded that evolution of the ankle and foot was the change that enabled species to move permanently from the ground into branches. His research on ankles and feet of various fossil and extant species supported this hypothesis. He wrote an article discussing his hypothesis and findings, had it translated and published in a Japanese science magazine with figures. [JA Jensen. “A New Oldest Bird?", 1981. Anima: 33-39. Tokyo.]

Honorary Doctorate

In 1971, Jensen was granted an honorary doctorate by Brigham Young University.

References



External links

See also

Ultrasaurus

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Last updated on Thursday September 18, 2008 at 06:26:30 PDT (GMT -0700)
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