James A. Jensen

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James A. Jensen in Preparation Lab at BYU with Ultrasaurus foot
James A. Jensen in Preparation Lab at BYU with Ultrasaurus foot

James A. Jensen (August 02, 1918 - December 14, 1998), a high-school dropout, became an internationally famous paleontologist. His aggressive collecting program spanning 23 years, mostly in the Utah-Colorado region of the USA, equaled that of Barnum Brown. Jensen frequently discovered new species which attracted the media, the public and fellow paleontologists. During the media coverage he was given the name "Dinosaur Jim". His greatest contribution to paleontology was to replace the awkward 19th Century web of metal struts, straps and posts for mounting dinosaurs with a system of internally concealed supports to produce graceful, free-standing skeletons.

Contents

[edit] Life to 1956

Jensen, born (1918) in Leamington, Utah, [1] developed a life-long love of dinosaurs while exploring the desert and mountains with his father hunting for Indian artifacts and fossils. He was unhappy with high school, with the effect of the Great Depression on the farm, and being the only working male on a small, hard-scrabble farm. At age 17, he left home without graduating from high school. In the next 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 wife to be, Marie M Merrell who lived in a now-defunct mining town of Mercur, Utah [2]. Ms. Merrell, like Jensen, came from a dirt-poor farm and never finished high school. [3] Casting about for ways to begin their life, they decided to homestead in Seward, Alaska. They married in Seward in 1941, and located land to homestead.[4]

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. [5] They had two children in Salt Lake City, Utah where he went through a crash training program to become a machinist and welder. He went to Hanford, WA to work on the nuclear reactor pile of the Manhattan Project, and then went to Pearl Harbor during the reconstruction. Jensen returned again to Utah where he worked at odd jobs, e.g. washing machine repairman, creamery man, truck driver, ceramics, gunsmithing, block printing, sculpting, welder, machinist, taxidermist, inventor, and writer. [6] He did taxidermy work for Arnie Lewis at the local Utah Field House of Natural History museum. In 1951, Jensen and his family returned to Seward, Alaska where he worked as a dock-side longshoreman for five years. [7]

[edit] Artist and sculptor

He was an enormously gifted artist who worked comfortably with most media. [8] His pastel and acrylic paintings, primarily of landscapes and American Indians, are hung from Alaska to Florida. He also sculpted in stone and plasticine, and used his welding skills as he deemed necessary.

[edit] Harvard University 1956 to 1961

Jensen was hired by Alfred Sherwood Romer at Harvard University in 1956, at the suggestion of Arnie Lewis. [9] 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, he went on collecting expeditions with Romer and Lewis to:

[edit] Kronosaurus Queenslandicus

Kronosaurus Queenslandicus before glass was added to exhibit. 1957-8
Kronosaurus Queenslandicus before glass was added to exhibit. 1957-8

Jensen assisted Romer and Lewis in mounting the Kronosaurus Queenslandicus(1956). He explained his vision of replacing the traditional cluttered 19th Century mounting method which utilized an external network of wires, straps, poles, and supports, with concealed supports which would leave the skeleton standing without any visible support. Jensen was granted permission to implement this vision. The final touch was to design a curved back wall that had no corners which created the impression that the skeleton was floating. (Romer, A. S. and A. D. Lewis. 1959. "A mounted skeleton of the giant Plesiosaur Kronosaurus". Breviora 112:1-15.)


Antrodemus skull suspended on little finger
Antrodemus skull suspended on little finger

Because of Jensen's experience in manufacturing and industry, he was aware of techniques and materials not generally used in museum displays. He experimented with "rigid foam" for casting light-weight models. He also experimented with the novel dental material “alginate” in 1958, as a way to obtain high fidelity reproductions. It had had great fidelity, but deteriorates when dried. Searching for ways to speed up the removal of matrix around bones while at Harvard (prior to 1961), he borrowed a Cavident which used ultrasonic waves through a tiny spatula, and experimented with a Cavitron which was a small sand blaster, neither of which provided an advantage.

[edit] Brigham Young University (1961 - 1984)

During the 23 years he worked at Brigham Young University, [10] he undertook an enormous program to collect new dinosaurs, educate, develop new mounting techniques, describe new specimens, and build a museum to house the massive collection of material that was collected. His collection work was localized in Western Colorado and Utah. In addition to the work in the U.S., he went on a second expedition with Harvard University to the Ichigualasto, Argentina, went on a speaking tour of Japan, Manila, and Singapore. He also went to New Zealand, Australia and Antarctica for 3 months.

[edit] High-yield exploration method

Jensen exploration method that yielded so many species, known and unknown, 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 covers only the 1960s and doesn't include all of the sites he worked in the 1960's. Note that if he visited multiple sites on a single outing, they are listed here in parentheses after the date. A "-" is used to separate each individual location. He did not find useful material at every site, but the number of types of specimens that he found is explained by this type of wide-ranging investigation and exploration. Note the frequency of personal names. They usually refer to rock hounds who had notified him of the possible site.

1961 Sept 27 Powder, Washington (He was hired by BYU in June, 1961)

1961 Sept 29 Lily Park (Disappointment Draw) to look at two sauropods.

1961 Sept 30 Green River - Fish Locality.

1961 Oct 6 Soldier Summit - Insect Locality.

1961 Oct 24 Grant Lloyd Gravel Pit in Santaquin.

1961 Oct 28 Fairview, UT sink-hole collected a mastodon jaw.

1962 May 25 Spanish Fork Canyon near Spanish Fork, Utah - Fossil fish locality.

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.)

1962 Summer (-Lily Park, -to Locality on the Yampa River, camping at “dinosaur draw”.)

1962 Aug/Sept Jensen/Jensen Quarry (J/62) near the Green River.

1962 Oct Third trip to Lily Park.

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.)

1963 April 15 Hell Creek, MT project Jordan, MT Montana.

1963 May 20-23 To Last Chance area.

1963 May 25 Willow Springs of the Last Chance.

1963 July 7-16 (To south-central Ferron Mountain in North Horn Formation, -Another locality “Fas Tank Hill”, -Collected mammal teeth and jaw fragments at Dairy Springs,-To Wood Tick Point below Ferron Reservoir, -North Horn Fm below Flagstaff -North Horn exposures East side of Singelton Flats. -In Black Dragon Canyon -Went toward “cap” on North Horn Mountain.)

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.)

1963 Oct 14 Last Chance Valley near Willow Springs.

1963 Oct 24-25 (To HB sites and collected plants, -To Muddy River -Down to Agate Gulch.)

1964 Jan 29-31 With James R. Jensen, went to Delta, CO.

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.)

1964 July 2 Willow Springs, UT area.

1964 Aug 11-22 (Grand Junction, Colorado and met with various, -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.)

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.)

1965 July 2-5 (Guided tour to Dead Horse Point State Park, Last Chance Ranch Road, -Vernal and Dinosaur National Monument.)

1965 Aug 15-17 (Moab, Armored dinosaur locality near Canyon Lands Airport.)

1965 Oct 6-8 (To Gazin lizard locality in Lower Joes Valley and South Dragon, -Prospecting; Kitchen Trail, Marys Lake Road, Cow Camp Road.)

1965 Oct 14-20 -To Quarry 20 miles NE of Moab.

1965 Nov 15-16 To a Morrison locality east of Castle Dale.

1966 Mar 21 Recon of Cad-1 locality and collected some bones.

1966 Mar 29-30 Dominguez Canyon locality.

1966 April 1 To Last Chance area west of Temple Mountain road.

1966 May 5-10 To Cad-1 locality to get it ready for geology class to dig.

1966 May 12-14 High on side of Escalante Canyon north of Delta (This site became Dry Mesa Quarry).

1966 May or June To locate Alamosaurus quarry near North Horn.

1967 April 3 (-Constructed long road to open Dominquez-Jones Quarry, Several film crews visited the site, and some geology classes.)

1967 Aug 21 Started on the Hinkle Allosaurus near the Utah-Colorado line.

1968 July Fremont River Bonebed (FRE/68) southwest of Caineville, UT.

1971 July 27 To Kaparowitz Formation off U 54 east of Henrieville, UT.

[edit] Dry Mesa Quarry

Starting in 1972, he focussed most of his work on Dry Mesa in Colorado. He worked in other locales, but he spent most of his time at Dry Mesa which is probably the richest quarry in North America in the second half of the 20th Century.

[edit] New dinosaurs

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

Species Discoverer
Camarasaurus lewisi Jensen, 1988
Cathetosaurus lewisi Jensen, 1988
Camarasaurus lewisi Jensen, 1988
Cathetosaurus lewisi Jensen, 1988
Dystylosaurus Jensen, 1985
Dystylosaurus edwini Jensen, 1985
Hypsilophodon wielandi Galton & Jensen, 1979
Iguanodon ottingeri Galton & Jensen, 1979
Palaeopteryx Jensen, 1981
Supersaurus Jensen, 1985
Supersaurus vivianae Jensen, 1985
Torvosaurus Galton & Jensen, 1979
Torvosaurus tanneri Galton & Jensen, 1979
Ultrasauros Jensen vide Olshevsky, 1991
Ultrasauros macintoshi Jensen vide Olshevsky, 1991
Ultrasauros macintoshi Jensen, 1985

He did not describe all of the new species that he collected so additional new species will be described for Dry Mesa.

[edit] 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. [11]

[edit] Legacy

[edit] Free-standing mounts

The technique for mounting free-standing dinosaurs was developed by Jensen in 1957, while participating in the mount of Kronosaurus Queenslandicus. [12] It remains his greatest contribution to paleontology and museum display and has disseminated throughout the world.

[edit] The Most challenging mount

Camptosaurus in the ultimate free-standing position, on one foot, on a narrow, thin point which is also free-standing
Camptosaurus in the ultimate free-standing position, on one foot, on a narrow, thin point which is also free-standing

Jensen’s last mount was that of a virtuoso who was in complete control of his materials and methods. He extended the free-standing concept to the ultimate level, mounting a medium-sized dinosaur in a running position, on one foot which is grasping a narrow, thin cantilevered ledge which itself is elevated 3 feet above the floor. As an artist, welder and machinist, he was able to fabricate a serpentine steel armature sufficiently small to be concealed inside of the skeleton, and sufficiently strong to support the double-scissor structure on three resting points. (See image) The design of the mount created a lever and fulcrum at each contact point, thereby multiplying the forces that had to be accounted for in the armature. The first resting-point is the right hip which supports the skeleton minus the right leg; the second resting-point which bears the entire weight is the junction of the right foot and the end of the ramp; the third resting point which supports the complete skeleton and 15 free-standing feet of the ramp is the joint formed by the rear end of that 15 foot segment and the top edge of the only vertical support for the ramp. The remainder of the ramp extends backwards to the floor. The cantilevered, double-scissor concept of this mount will not be surpassed until levitation is practical.

[edit] Plastic foam casting

While at Harvard, Jensen pioneered the use of plastic foam 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.

[edit] Museum built around a single ramp

In the 1963-64, he designed a museum based on a revolutionary idea: construct the entire museum around a single, continuous ramp that started at one corner of the ground floor snaking around the building on its way to the top, representing the evolution of life on the 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.

[edit] Cooperation with rock hounds

Part of his remarkable 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.

[edit] Education

Another legacy was Jensen's urge to educate the public about dinosaurs. Today, most new books about dinosaurs include stories of ultrasaurus and supersaurus two of his favorite specimens that he spoke about when he could. 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. [13] 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.

[edit] Notes

[edit] 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, and then destroyed all English copies of the manuscript. [JA Jensen. “A New Oldest Bird?", 1981. Anima: 33-39. Tokyo. - IN JAPANESE only]

[edit] Honorary Doctorate

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

[edit] References

[edit] External links

[edit] See also

Ultrasaurus

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