Echinoderms flourish in warm, shallow seas. They include sea urchins, starfish, sea lilies, sand dollars and related animals with external skeletons composed of small, limy plates held together by soft tissue. Echinoderms evolved some 400 million years ago and reached the zenith of their biological vigor about 100 million years later.

During that period Iowa was an ooze at the bottom of a vast inland sea. The sea has washed over much of the U. S. midwest on at least eight occasions during the past billion years. Geologists do not agree on the precise cause of the periodic flooding. But many details concerning its frequency, extent, duration and associated climate have been explained by analysis of the sediments laid down by the water and fossils trapped in the resulting rock.

In general each period of flooding followed an interval of crustal unrest during which the earth was disturbed by volcanic action and mountain building accompanied by the accumulation of glacial ice on the land. In the period of upheaval the midwest stood above sea level. Gradually the crust settled down, erosion rounded off the mountains, the glacial belt retreated to the north and eventually the planed-down midwest area fell below the sea level again. Then for millions of years life teemed in the balmy climate. So each of these cyclic periods in the history of our continent is marked in the rocks by the fossil remains of plants and animals which rose to dominance and flourished until buried by a new upheaval.

Half a billion years ago trilobites, primitive three-lobed marine animals resembling the modern horseshoe crab, populated the waters on Iowa in immense numbers. The fishes followed 200 million years later. Another 200 million years saw the rise of dinosaurs. Other organisms similarly held the center of the stage at other periods. One of these was a representative of Mr. Beane's echinoderms: the sea lily, or crinoid. The echinoderms, immediate successors in the evolutionary chain to the coelenterates (which include jellyfish, sea anemones and hydra), developed a remarkable skeleton, a nervous system, a vascular system, a digestive tube distinct from the body cavity and a sexual mode of reproduction.

Echinoderms typically have a radially symmetrical form, as In the starfish. In addition to the rayed structure, sea lilies are provided with a stalk which extends down from the center of the body to a rootlike structure at the lower end which enables the animal to grasp the bottom. Its petal-like arms wave continuously in search of food, and any particles encountered are conveyed down a groove to the mouth at the center.

After death the soft tissues binding the skeleton disintegrate, and water currents scatter the minute plates over the bottom, where they are usually crushed beyond recognition by the weight of accumulating debris. During the mid-Mississippian period some 300 million years ago, often called "the age echinoderms," a great deal of limestone was formed by this process, and in some midwestern localities the beds are nearly half a mile thick, interrupted only occasionally by veins of shale or sandstone marking intervals when the inland sea temporarily withdrew.

Until the discovery of the LeGrand fossils, few paleontologists had ever seen a complete fossil specimen of a crinoid. But under certain conditions- e.g., quick burial under a thin layer of silt which excludes oxygen and bacterial invasion-the soft tissue of a crinoid may be replaced by deposits of calcium and magnesium compounds. These conditions were met in a remarkable way in a small area of what is now a rock quarry about a half-mile north of LeGrand. There the first major deposit of crinoids was discovered 75 years ago.

"This quarry," writes Beane, "has served for more than a century as a major source of stone used in the construction of the Iowa buildings and highways. The Kinderhook beds at LeGrand are an outcrop of the Hampton formation. Descriptions of crinoid fossils discovered here have appeared in geological literature since 1890. Fragments of individual fossils were discovered in the vicinity by James Hall, a New York State geologist, in 1858. But the first really productive deposit was uncovered 40 years later, when workmen operating on one of the rock ledges near the Iowa River in the south half of the quarry came upon a circular colony of echinoderms, mostly crinoids, at a depth of about 20 feet. Crinoids are gregarious animals, and hundreds were recovered from the deposit in excellent preservation. Evidently the colony was killed quickly-perhaps a slide of some sort roiled the bottom and they suffocated- because all of the specimens are found in a single zone of the rock. The stems lie in random directions, indicating that the colony lived in still water.

"This discovery created quite a stir: le among scientists of the day, and during the next decade several of the nation's: foremost paleontologists and geologists visited LeGrand. They were the idols of my boyhood. I pestered them with endless questions and they answered with inexhaustible patience. I became a fossil collector and have been at it ever since."

After the first deposit was picked clean of fossils, pickings were lean for 40 years. "You locate crinoids," says Beane, "by examining the edge of the rock for a fossil outcrop. From the turn of the century until 1931 I must have examined a thousand tons of loose rock as well as keeping a close eye on the entire quarry face. About one rock in 500 would turn out to be fossiliferous, and not more than 1 or 2 per cent of these yielded interesting specimens.

"Then one day in 1931 a blast uncovered the edge of a spectacular colony of crinoids about 100 feet from the initial find. It was somewhat smaller, a lens-shaped deposit about 15 feet across, but the specimens were in a state of almost perfect preservation. Doubtless many choice fragments loosened by the blast went to the rock crusher before I got on the job. But even so, scores of museums now own beautiful specimens from this deposit. From then on I kept continuous watch of every square inch of quarry face in the near vicinity as it was uncovered. The scrutiny paid off in 1933 with a truly big discovery. Evidence of specimens appeared in the familiar zone at a point about 50 feet from the colony discovered in 1931.

"The quarry owner generously agreed to work out the slab by hand, which proved to be an expensive undertaking because the fossiliferous zone was situated 25 feet below the surface of the ]edge. The overburden was carefully drilled and shot away, after which the slab was removed in sections of various sizes about two feet thick. The colony measured more than 20 feet in diameter, and its full removal took four years.

"The sections were transported to my back yard, where I have an open-air shop equipped with a strong bench, block and tackle and a low stool. The preparation of the specimens for display is as simple as the tools with which the: work is accomplished. In addition to the workbench, you need only a geologist's or a stonemason's hammer, a toothbrush and a fine needle gripped in a pin vise.

"Examination of the edge shows the thin horizon, or bedding plane, in which the fossils are located. After the section is worked down to within a few inches, of the fossils on each side, the slab is split at the critical horizon by tapping the edge with the sharp face of the hammer. Eventually the tapping will open a small crack. A magnifying glass is used for locating the cleavage zone, and some workers mark it with a lead pencil before attempting to make the split. The art of hitting accurately with the hammer is easily mastered with practice. Fine nails, which serve as wedges, are then driven partly into the crack every half inch around the slab. Successively heavier nails are used to widen it until the slab parts. With luck you get a clean separation. Most of the fossils will cling to orie slab, the opposite half showing matching depressions. Invariably fragments of the limestone matrix cling to some specimens, obscuring the fine detail or even large portions of the body. Removing the matrix can be a long and tedious job. Fortunately it is usually softer than the specimen, and some of it can be scrubbed away with a moistened toothbrush. When the toothbrush has done its work, the remaining part of the matrix is picked away with the sewing needle. Depending on the size of the slab and how cleanly it split, the needle job will require from three hours to three months. I have been working on one exceptionally large specimen off and on during the past 80 years.

"It is evident that echinoderm fossils are not easily come by, and until 20 years ago I kept every specimen I found. I was under the illusion that the satisfaction one derived from the hobby increased in proportion to the size of his collection. Then, at a geologist's suggestion, I visited the Morrill Hall Museum. at the University of Nebraska. There I met Dr. Erwin H. Barbour, the curator and showed him a couple of my crinoids. After examining them, he asked if I would make some specimens available to the University. He listened patiently as I explained how I felt about my collection and then said: 'Mr. Beane, we should have a heart-to-heart talk. You own hundreds of exceedingly rare fossils, and it is wrong for you to keep them in your little village. They should be widely distributed to universities and museums for students to study and for the public to admire.' By the time our discussion, ended I understood, for the first time, the obligation under which the amateur collector works and the contribution he can make to science.

"Shortly afterward I presented Barbour's museum with some items in my collection, including a slab which measured two by three feet and contained more than 200 crinoids and stems. He was delighted, and within a short time published an illustrated description of the fossils, in which I received credit as the collector. My mail was soon full of requests for collections from various institutions. About half of the universities in the U. S. and many museums abroad now own LeGrand crinoids.

"I must confess that the resulting expressions of gratitude have far outweighed the satisfaction which came with owning a ton or so of rock. Raymond C. Moore, the state geologist of Kansas and head of the geology department of the State University, visited me a few years ago and after examining my remaining specimens said: 'Mr. Beane, I must hand you a bouquet. You have put the little town of LeGrand on the map of the world where many larger communities will never appear.'

"Perhaps the greatest thrill of my collecting career came in 1930. I split a slab measuring approximately three by five feet. To my astonishment I counted 183 perfect starfish, along with 12 sea urchins, two trilobites and a sea lily! According to Charles Schuchert of Yale University, it was the greatest find of fossil starfish ever made. This is the specimen on which I have worked so long.

"I must mention one example of the privileges that open to an amateur who learns to share the fruits of his hobby. In 1937 I was invited to collaborate with Lowell R. Laudon of the University of Tulsa in a study of LeGrand crinoids and to publish with him a comprehensive description of all our local species. I was given the additional honor of naming 11 new species in recognition of friends. I named one of them for George F. Kirby, owner of the LeGrand quarry, whose generosity enabled me to enjoy a lifelong hobby."

The version of the Van de Graaff machine described here last year has a rubber belt which runs between a pair of pulleys, one made of metal and the other of polyethylene. They are enclosed in insulated housings that serve as high-voltage terminals. Static electricity, generated frictionally between the belt and the polyethylene pulley, is transported by the belt to the metal pulley, where the charge is transferred to the terminal by a comb of metal points. The work expended in moving the charge up the belt increases the voltage. Machines of this type employing belts an inch wide and a foot or so long can generate a continuous current of several microamperes at potentials up to 100,000 volts. They permit scores of fascinating experiments, particularly those involving gas discharge tubes.

A number of amateurs have requested more specific information about the construction details of the "baby" Van de Graaff. Hedley writes the following report on his machine.

"I have now made two Van de Graaffs, the first substantially the same as the one described in 'The Amateur Scientist.' The second machine is twice as large [see photograph, right ]. It performs quite satisfactorily, giving bright intermittent sparks about four inches long and weaker ones six inches or more in length when one's hand is brought near the underside of the terminal.

"The machine is supported by a housing which encloses the motor and lower comb assembly. The housing consists of 1/16-inch sheet steel welded to form a rectangular box measuring six inches high, six inches wide and eleven inches long, the base being of 3/16-inch steel. A detachable cover at one end provides access to the motor. One side can also be removed for exposing the pulley, comb assembly and belt.

"The belt is powered by a series-wound motor (Royal Air Force war surplus) which runs under full load at a speed of 6,000 revolutions per minute. This is fitted with a pulley machined from polyethylene, one and a quarter inches in diameter and one and three quarters inches long. It is crowned slightly and makes a driven fit with the shaft. A wooden pulley of the same size with a jacket of polyethylene would work equally well. The jacket could be covered with a layer of polyethylene friction tape of the kind now sold by dealers in electrical supplies, or it could be made of a cylindrical section cut from one of the small polyethylene bottles in which cosmetic preparations are commonly sold.

"The lower comb assembly consists of a bracket made of 1/16-inch sheet copper, an inch and five eighths wide, to which six tufts of number 86 copper wire are soldered at one end. The wires are spread out to form an even row and clipped straight at the ends [see drawing in Figure 5]. The brush assembly is bolted to the base plate and adjusted to bring the wire comb slightly above the center of the pulley.

"A switch for operating the motor and a small neon bulb are mounted in the fixed side of the housing. The lamp glows when the machine is operating properly. Originally I mounted it on top of the housing but lost several bulbs when they were perforated by high-voltage sparks!

"A tube of clear plastic, three inches in diameter and 18 inches long, which makes a push fit with a polished pipe flange bolted to the housing, supports the upper terminal. The inner threads are filed from the flange prior to assembly. The upper end of the tubing is beveled, and two holes are drilled on the diameter to receive a pair of ball bearings. A X-inch shaft turns in these and supports a crowned brass pulley which matches the size of the lower pulley. The pulley makes a sliding fit with the shaft and is anchored with a set screw. This arrangement provides for easy disassembly when changing the belt.

"The high-voltage terminal consists of a nine-inch spherical copper float of the type commonly used in industrial plumbing. It is split on the diameter by means of a thin hack-saw blade. A flat, narrow ring is soldered to the inner edge of the lower half, on which the upper half makes a snug fit and clean joint. A two-inch hole is cut in the center of the lower hemisphere and the metal is worked into a doughnut shape by means of a rawhide hammer and rounded anvil. A cylindrical collar is then soldered to the inner face of the re-entrant edge for an easy fit with the plastic tubing. The upper collecting comb is bolted to a lug soldered to the inner surface of the lower hemisphere. A kink in the bracket provides for final adjustment relative to the center of the upper pulley.

"A disk of 1/4-inch plastic, six inches in diameter, serves as a platform for supporting the upper terminal. A hole is cut in the center for admitting the plastic tube, to which the disk is fastened by one of the quick-drying plastic cements. In addition to supporting the terminal, the disk minimizes corona discharge from the bottom of the terminal. A discharge gap is provided at the side of the machine, as shown in the drawings.

"These machines are sensitive to the high humidity prevalent in England, and for reliable operation I found it necessary to install a 50-watt heating element inside the motor housing. My next project will be a Van de Graaff of the type in which the charge is sprayed onto the belt at the lower pulley by a high-voltage source. I should appreciate any constructional tips that amateurs who have built such machines would care to pass along."

Bibliography

THE CRINOID FAUNA OF THE HAMPTON FORMATION AT LEGRAND, IOWA. L. R. Laudon and B. H. Beane in University of Iowa Studies: Studies in Natural History, Vol. 17, No. 6; December, 1937.

MODERNITY IN PALEOZOIC STARFISHES. Charles Keyes and B. H. Beane in The Pan-American Geologist, Vol. 62, No. 3, pages 197-212; October, 1934.

Suppliers and Organizations

The Society for Amateur Scientists
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East Greenwich, RI 02818
Phone: 1-401-823-7800

Internet: http://www.sas.org/