Cataloging And Displaying Fossils

A jumble of fossils on a shelf is nothing but a heap of curiosities of neither scientific nor monetary value. Among them may lie a one-of-a-kind fossil, a new species, perhaps even a "missing link" that could throw light on the relationships of some group of plants or animals. Or a common fossil may take on new interest because it is from a locality where such a species has not been found before or from a rock series in which it has never been seen previously. But if the fossil has not been carefully labeled and cataloged with the exact location and rock layer in which it was found, it has lost all significance. Recording, labeling, and displaying are the steps by which the collector educates himself as well as contributes his bit to the science of paleontology.


All fossils should be labeled as soon as possible. Fossils taken from separate formations should be separated in the field. Fossils from one location should not be mixed with those from another, even though the two localities are only half a mile apart. The fossils may be from similar but distinct formations. Furthermore, discards from one site should not be dumped at another site; they should be saved for the driveway. Dumping them thoughtlessly may thoroughly confuse research on that locality.

Most fossils found by the amateur will be loose — weathered free from the matrix. If they are collected in matrix, the blocks of rock containing the fossils will probably be found some distance from their source. This makes it difficult to say with certainty which layer contained the fossils. They should be so labeled.

Few amateurs have to go through the sweat and tears of mining out layers of rock to be sure that fossils are found in place. This is what the professional must do; the loose fossils so readily available are only colorful objects to him. If a fossil is taken from a specific layer of rock, the general description of the rock layer should be noted on the catalog card for the fossil; for example, a record might read, "thin, three-inch gray limestone lying below a one-inch black shale and three feet above a thin coal seam."

The location information should be as specific as possible. This could be the name of the quarry, a specific spot in a river (such as "100 yards downstream from crossing of State 41"), roadcut (described by milepost or mileage from important junction or river crossing), or beach cliff (distance from some prominent feature). The best description is by precise position within a township. This would have to be done by reference to a quadrangle map (see Chapter VIII). An exact description will outlast road changes, river meandering, fluctuating city limits, and filled quarries. There are many fossils in old museum collections with descriptions of locations such as "300 rods southwest of Mills Ferry Crossing." A town now thrives where Mills ferried a century ago, and nobody now knows where the crossing was.

A label can be written on a piece of paper and wrapped with the fossils in the field, or the bag or box can be labeled. As much information as possible should be included at the time; memory fades fast.


As soon as the fossils have been prepared at home, they should be cataloged. Each specimen should have a catalog number, even though twenty from the same locality are kept for display or research. All can be given the same number if they are identical, or each can be given the same number followed by a different letter.

There are as many systems of numbering as there are collectors. The easiest system is to start with the first fossil as No. 1 and number specimens as they are received. Another is to start with a letter followed by a number: the letter referring to the fossil phylum, period, or locality, and the number to its order of acquisition.

After the paint has dried, number the fossil with India ink. When it is dry, seal it with a dab of household cement. Save old labels, such as this 19th-century English one.

The most permanent method of labeling a specimen is to write the number on the specimen in some obscure place. On light-colored matrix this can be done with a pen fitted with a fine nib (such as a crow-quill pen) using India ink. The number can be written directly on the matrix. The India ink will be permanent. On dark matrix, such as black shale, white ink can be used, but this is not as permanent.

For uniformity, a splotch of white can be painted on the specimen to receive the number in India ink. The white enamel or lacquer sold in most hobby shops for model painting is excellent. A strip of paint the width of a paper match and a quarter inch long will easily hold a four-digit number; in fact, a match makes a good throw-away paintbrush.

The paint is dry enough to write on in ten minutes. If a mistake is made, the India ink can be washed off immediately. After the ink is thoroughly dry, at least fifteen minutes, paint a thin layer of plastic household cement (such as Duco) over the number. Do this rapidly in one stroke, as the cement will smear the ink if it is brushed on. The cement protects the number from wear and from repeated washings.

On exceptionally rough matrix, such as sandstone, a thick layer of household cement will smooth the spot before painting.

Paint the number on the matrix rather than directly on the fossil. If the actual fossil must be numbered, do it in a spot that will be hidden when the specimen is displayed and in an area not vital for proper identification. Tiny fossils may not have room for a splotch of white. If they are not porous they can be numbered directly with ink.

The number should be entered in a catalog along with pertinent data. Some collectors prefer a double system of bookkeeping, with brief description in one book for rapid referral, and another book or series of index cards containing full data. An entry should include names of the fossil, precise location where found, age and formation when known, date collected, and any comments of interest about the fossil. It is helpful to include a description of the fossil, listing size, condition, and even approximate value. If a specimen is purchased, the dealer's name and price should be included. Having two separate catalogs will be added protection if one is lost. Whenever making an entry, try to enter a description that would make sense to the museum curator who may acquire the collection many years later.


Entire books could be written about techniques of display. Museums hire artists and decorators to prepare exhibits that are educational and inter esting to the public. The amateur may keep his collection tucked away in drawers or shoeboxes, or he may display it so as to amaze and delight his neighbors and instruct the local Cub Scouts.

Cabinets and Drawers

Most fossils are small —several inches long or less —and are unimpressive if hidden behind other specimens on wide shelves. The usual wooden shelves, china cabinets, or department-store display cases are not well designed for small fossils, which are best seen in an open tray, such as a shallow drawer or a flat case not more than a few inches deep covered with glass. If an upright case must be used, it should not be deep, or the fossils in the rear rows will be poorly lighted. Since few fossils have the overpowering color and beauty of fine minerals, most visitors to a basement museum prefer to look at only a few cases of particularly interesting specimens. The rare ones of interest only to collectors can be kept in drawers.

Museums and universities house collections in cabinets that may stand thirty drawers high. Each drawer is about twenty-four inches square and two inches deep. Few specimens except some cephalopods, giant corals, and vertebrate fossils are too large to fit into such a drawer. Drawers can be built at home or can be bought in sections from geological-supply houses (see Appendix). Dentists' and typesetters' cabinets and map-storage units for libraries occasionally appear on the market. They are excellent, although a bit shallow. Drawers have many advantages. They afford a maximum of usable display space; they take up little space themselves and they keep specimens free of dust. Furthermore, specimens can be examined closely in drawers and even removed for closer inspection, if desired.

Specimens on large thin slabs can be hung from nails or pegboards by hooks attached to their backs with tape or epoxy.

Flat display cases can be built from shallow drawers or from two-by-one-inch lumber (furring strips) attached to a plywood backing. A thin railing of wooden molding strip can be attached inside the case an eighth of an inch below the top, just deep enough for a sheet of thin glass to be flush with the surface when resting on this railing. A small hole in one side allows a finger to slide under and lift up the glass when it is to be removed for cleaning or for changing specimens. These cases can be built in a variety of shapes and sizes to sit atop tables or benches.

Small fossils can be displayed in the cardboard cases known as Riker mounts. These are a foot or less long and an inch deep. They are filled with cotton, have a glass cover, and are not very expensive.

Museum-type method of arranging and storing fossil collection in shallow trays placed in drawers. Each tray contains card with place, date, and collector of the fossil, and vertical card with catalog number, name, and other data for quick reference. Collector is shown comparing a specimen ammonite with reference book. (Photo California Division of Mines and Geology)

Museum-type method of arranging and storing fossil collection in shallow trays placed in drawers. Each tray contains card with place, date, and collector of the fossil, and vertical card with catalog number, name, and other data for quick reference. Collector is shown comparing a specimen ammonite with reference book. (Photo California Division of Mines and Geology)

Backgrounds and Supports

Fossils are not colorful, and a good display will take advantage of background material and props to please the eye. Flat cases and drawers should be lined with some material that will help stop round fossils from rolling every time the drawer is opened. The best background for most fossils is a dark material of fine texture, unless the fossils are very large. Black con-

Styrofoam blocks make attractive mounts for dark-colored fossils. The front of the block can be beveled and a label attached with pins.

struction paper is cheap and can be cut to fit a drawer without overlapping. Black cloth is even better.

In china cabinets or other large cases with shelves, specimens will have to be supported in position. This can be done by cutting the matrix into a block so that the specimen sits upright, or the fossil can be pressed into a piece of styrofoam. Small blobs of non-oily clay or Play-Do can be molded to the bottom of the fossil as a base. Oily clays will transfer their oil to the specimen; it will soak irretrievably into the fossil. Sometimes a small piece of styrofoam or wadded paper put behind the specimen will hold it at a proper angle. There is no need to glue a specimen to a block of wood, plastic, or styrofoam unless it is for a permanent museum display.

Grouping Fossils for Display

Fossil displays are usually arranged either by groups of plants or animals or by age. Trilobites would be in one section, fossil ferns in another, and brachiopods in a third. Fine displays have also been created by grouping fossils from one locality. In competitive displays at rock-club shows and geological-society conventions, fossils are often exhibited in other classifications, such as fossils personally collected; fossils of one genus or family; fossils showing replacement by other minerals; fossils of a certain size

(such as microfossils); or fossils displayed to show variety of forms within one small group. These themes make home displays more interesting than endless rows of battered brachiopods collected over the last decade from the local gravel pit.

Repairs and Retouching

For display purposes, some fossils may need to be touched up to enhance their good features. But they should only be touched up, not repainted, refinished, or remodeled. Even after careful preparation, a fossil may have so little color contrast with the matrix that it is hard to see. This is particularly true of fossil leaves and soft-bodied animals that are only a film on the rock. Such specimens should never be coated with shellac or paint to bring out contrast, as this may destroy the fine features needed for identification.

Many plant fossils from Illinois and Indiana have been daubed with thick, shiny varnish or shellac, which not only decreases contrast but also leaves an annoyingly shiny surface that is impossible to remove.

Fossils that need increased contrast should be coated with yellow dextrin, an inexpensive substance formerly used in baby food. It can be obtained at large drugstores or at some rock shops. White dextrim will not work; demand the yellow. A pinch of the yellow powder dissolved in a teaspoon of hot water will coat several dozen fossils. Apply the dextrin with an artists' paintbrush, and be careful not to paint the matrix. The coating should darken the fossil without leaving a particularly shiny surface. If it is too shiny, the amount of dextrin in the mixture should be decreased. Mistakes can be washed away in warm water.

Some specimens benefit from an all-over bath of the dextrin, while others look better with the matrix painted and the fossil left untouched. Experiment, but if you can't do it with dextrin, you can't do it with paint, varnish, or plastic, either.

Now and then, specimens that have been unfairly restored appear in collections. Black carbonized-fern fossils missing some of their detail have been restored with touches of India ink. Normally dark-brown or black trilobites have been made more so with a lustrous coating of shoe polish. Missing spines of some fossils are scratched into the matrix and colored. Plates of unusual fossil combinations are concocted by gluing specimens in desired places. Whether such things belong in a fossil collection is a question that must be left to the conscience of the collector.

Some small repairs are permissible. It is fair to cover up glue joints in broken specimens. When repairing a broken fossil, take care not to allow

Before treatment, this fossil fern lacked contrast with its matrix.
The fossil, painted with weak yellow dextrin solution, shows improved contrast. Matrix is not painted.

surplus cement to show at the surface. Dust the exposed top of the crack with scrapings from the fossil matrix; when the glue dries the crack will be camouflaged. Holes and chipped areas can be refilled with a dough made of epoxy and rock dust of the proper color. Fossil bones missing some portions or skeletons missing some bones often are filled into their original form in museum preparations. Plaster is used to do this, and usually the museum is careful to color this plaster so that it is noticeably different from the real bones.


Many fossil collectors will never wish to take pictures of their prizes, but some will want to make color slides to illustrate lectures or black-and-

white prints to submit with articles. They will find that photographing fossils is a specialized aspect of the craft.

Most fossils are only an inch or two long, too small to be photographed with inexpensive fixed-lens cameras that cannot be adapted for closeup lenses. A good 35 mm. single-lens reflex camera with a fast lens and a set of extension tubes or a bellows is necessary for color slides. It also works well for black-and-white print photography. Larger cameras, from l\" x 2\" to 4" x 5" press cameras, are excellent if prints are wanted.

Portrait or closeup lenses are sold for attachment to cameras with fixed lenses. These are not expensive and will produce good pictures of large fossil specimens. Some lenses bring the camera into focus within a few inches of the specimen, but unless the photographer is a good guesser, the fossil will rarely be centered in the film.

The single-lens reflex camera has certain advantages for this type of work. It allows sighting directly through the lens that will take the picture instead of through the auxiliary viewing lens which is an inch above the real lens. In distance shots, both lenses see essentially the same picture, but in closeups a small fossil that appears directly centered through the auxiliary viewing lens may not even appear in the final picture. The single-lens reflex shows things exactly as they will appear on the film, even including the depth of field.

Numerous books that explain how to take closeup pictures of small objects are available in camera shops. One of these books should be consulted for its tables about magnification achieved with combinations of different portrait lenses and extensions of the lens from the camera body. As the camera lens is moved farther away from the film, the image size becomes larger and larger until a small fossil completely fills a negative. By the use of bellows or extension tubes two- or threefold magnification can be achieved, which is more than ample for normal photography. Higher magnifications can be made by using a microscope with camera attachment.

Two things happen when extension tubes or bellows are used. The exposure time increases dramatically but according to a definite formula that will be listed in any book about closeup photography. The depth of field also decreases, until at the magnification needed to take a picture of a one-inch brachiopod with a 35 mm. camera only a fraction of an inch will be in focus. This means that much of any rounded fossil will be out of focus. Small lens-apertures of f/32 or f/64 help increase this slim depth of field, as do special lenses designed for closeup photography. A book or a professional photographer should be consulted about these.

Fast film and a sturdy tripod are needed for color-slide photography. If a lens extension or portrait lens is used, the exposure time, even with fast film and bright sunlight, will still be too long to get a sharp picture with a hand-held camera. Ektachrome is the favored film, but Anscochrome works well. Kodachrome is excellent, but slower. European color films work well.

Outdoor Lighting

Whenever possible, photography should be done outdoors to take advantage of the light, which is at its best for fossils in the morning and late afternoon. Around noon, the overhead sun does not cast shadows in the low spots of a specimen, and without this modeling the fossil will look flat and drab. Very early or very late sunlight should also be avoided for color photography because it creates too many shadows and is excessively orange.

The camera should be mounted atop the tripod at a convenient level. A table or platform is needed to bring the specimen up to the camera level. Some specimens should be photographed on a background of textured cloth, while others look better "floating" above an out-of-focus background. This effect is created by placing the fossil on a large glass shelf supported at least two feet above the ground. The ground is covered with cloth or paper of an appropriate color. It will be out of focus in the picture. The glass shelf, unless dusty, will be invisible in the picture.

Reflections are a problem when using glass, and the photographer may wind up with a picture of a fossil sitting inside a reflection of the photographer taking the picture. After sighting through the lens to make sure no reflections are seen in the picture, the photographer may move his head a few inches to snap the picture and inadvertently create a bad reflection.

Few fossils will pose well by themselves. They need to be coaxed into position by props made of modeling clay or wadded paper. The surface of the fossil should be placed so that it is parallel with the lens to make sure that all of it will be in focus.

Since camera movement is magnified as much as the fossil in closeups, long exposures require use of a cable release. The movement of the mirror during exposure in a single-lens reflex camera creates vibrations, and this is compounded if the shutter is released manually. A breeze can jiggle camera or specimen enough to make a blurry picture; so can a passing truck.

If the camera has a behind-the-Iens meter, the exact exposure time and lens aperture can be accurately and immediately read. If the meter is located elsewhere on the camera or is separate, allowance must be made by increasing the exposure to compensate for use of bellows or extension tubes. This can be determined by experiment or from tables supplied by camera manufacturers.

Pictures can be taken indoors using artificial lighting, but for the occasional photographer the bother of acquiring the necessary equipment and of setting it up is hardly worthwhile. There will be many days when good pictures can be made outdoors. Brilliant sunshine is not needed; a hazy day or one with thin clouds is fine, as such lighting softens the contrast between the shadows and highlights and seems to make colors richer. Dark shadows can be reduced on a sunny day by holding a piece of frosted glass, cloudy plastic, or thin fiberglass matting above the specimen to diffuse the sunlight. Dark shadows can be filled in by placing a piece of aluminum foil or white paper to the side of the specimen so that sunlight is reflected into the dark areas. Exposures should be figured with these devices in place.

Black-and-white photography is the most highly developed form for fossils. Prints made for reproduction in journals, magazines, and books must be of high quality because the print will lose some detail even with the best reproduction.

Improving Contrast

Fossils rarely have an even color. When photographed, blotches and stains look like shadows and obscure the real shape of the fossil. A dark specimen is difficult to light: there must be sufficient contrast between the highlights and shadows to show the three-dimensionality of the specimen. A white fossil photographs best of all, so a blotchy fossil can be whitened temporarily for photography. There are three different methods of doing this.

The easiest way, and one that is used professionally, is to coat the specimen with magnesium oxide. This does not harm the specimen, because it can be washed off after the fossil is photographed. A piece of magnesium ribbon several inches long is held by one end with a long pair of tweezers or pliers. The free end is lit by holding it in a gas flame or cigarette lighter for a few seconds. Magnesium, a metal, burns with a brilliant, intense flame and gives off clouds of white smoke. This white smoke is magnesium oxide.

The specimen should be held by one corner with a pair of tweezers and placed several inches above the burning magnesium strip. The strip burns for only a few seconds, so the work must be done quickly. It is wise to wear sunglasses to cut down the brilliant glare from the burning magnesium. If the specimen is held in one place, essentially parallel with the smoke column rather than at right angles to it, more of the white oxide will be deposited on one side of the bumps and corrugations of the fossil surface than on the other side. This delineates these features and in the photograph will look quite natural. The coating is so fine that no surface detail is lost, and if the result is not satisfactory the specimen is easily cleaned and resmoked.

A more controlled deposit of fine white powder can be made with ammonium chloride. A bottle of dilute hydrochloric acid and a bottle of ammonia (ammonium hydroxide) are connected with glass tubing that runs through a rubber stopper in the top of each bottle. Air is forced into the first bottle by blowing through a separate tube, driving the combined vapors of the two chemicals through another glass tube (see illustration). The combination creates ammonium chloride, a fine, white powder that is deposited on the fossil held in front of the exit tube. It is easier to control this chemical fogging than that from the rapidly burning mag-

Fossil Infrared Photography

hydrochloric acid ^

ammonium hydroxide

Fossil is whitened for photographing by blowing fumes of hydrochloric acid and ammonia simultaneously through both tubes. The white powder forms as the fumes meet at the fossil.

nesium ribbon, though the apparatus is clumsy. Excessive humidity will cause the ammonium chloride coating to disappear. After the photograph has been taken, the fossil can be washed clean.

A third method, the least satisfactory but better than none, is to dip the specimen in thinned white watercolor paint or nonpermanent white ink. This may sink into the specimen and ruin it; try a scrap fossil before whitewashing a good one.

The ultimate in contrast is produced by dipping the specimen in India ink before coating it with one of the whitening agents. The whitening chemical is directed onto the specimen so that only the highlights are whitened, leaving the low spots coal-black. A fossil treated this way will clearly show every tiny pore and ridge in impressive contrast. Unfortunately, the India ink remains a permanent part of the fossil.

Photographing Fluorescence

Fluorescence of fossils can be photographed. Inexpensive black light bulbs are adequate light sources for photographing most fluorescent fossils, such as the mysterious insects from Solnhofen, Germany, or the color patterns in snails and clams that are invisible in normal lighting. There is an added advantage; in ultraviolet light the depth of field is markedly increased, allowing more of the surface of a rounded specimen to be in focus. Fast panchromatic film must be used for black and white pictures, but even then exposures are extremely long, often over thirty minutes. Filters such as Kodak Wratten 2A, 2f3, or K2, Ilford Q, or Corning Noviol C must be used. Color slides can be made with Kodachrome or similar films, without using filters.

Infrared Photography

At the other end of the invisible wave lengths of light is another interesting field of photography— the infrared. Contrast is often much improved in fossils photographed in infrared light. Fish scales or graptolites are transparent in infrared light, and crustaceans in dark shales photograph much more clearly. This contrast cannot be seen by the naked eye, so the fossil must be photographed in order to find out whether contrast is indeed improved.

Any tungsten bulb (regular light bulb) is a satisfactory source of infrared radiation, but a camera filter such as Kodak Wratten 25A or 87, Agfa 85, or Ilford 207 must be used. Special infrared film is available, and the film must be developed in the dark. No safelight may be used. Cameras must be in perfect condition, as the bellows or wood used in some cameras may leak infrared light even though they are impervious to visible light. Since infrared light focuses at a different spot from visible light, the lens should either be moved slightly farther away from the film after focusing in normal light, or a very small lens opening should be used to compensate for the change in focus.

Developing and printing photographs of fossils is carried on just as with other pictures.

Photographs for Publication

For publication, most editors prefer a glossy print with good contrast that is at least five by seven inches in size. Several fossils can be photographed together on one plate if they can be kept in focus. Lighting should always be from the upper-left corner (this is a standard accepted by all professional paleontologists). When submitting photographs to a magazine, be sure to include in the mailing envelope a thick piece of cardboard as large as the largest photograph. This will dissuade the postman from folding the package when he stuffs it into the mailbox. Write clearly on the envelope: Photos—Do Not Bend or Fold.

Never write captions or identification on the reverse of the prints; the writing will show through as raised script when the print is reproduced. Identification information should be on a separate sheet but not stapled or clipped to the photograph. Paper clips press into the photographic paper under the weight of other letters in the post office. If writing must be done, do it on the margin of the photograph, preferably with a crayon or a grease pencil.

Be sure to note the degree of magnification or reduction of the fossils as they appear in the photograph or to include the actual size of the specimens in the notes. If a one-inch fossil is three inches long in the photograph, this is expressed as x3; if a three-inch fossil is only one inch long in the photograph, it is xj. It is helpful to consult the Journal of Paleontology to see how a typical article is illustrated.


When the collector gets home, unpacks his trophies, and cleans and labels them, he will often find that he has duplicates of some species. He is now in a position to augment his collection by trading with other collectors.

Trading can be done at the many mineral- and fossil-club shows held throughout the nation, and at the conventions held annually by the six major mineral and geological society federations. Swaps can be arranged between persons who have met at such shows or who have obtained each other's names by mail or by advertising in the several amateur hobby magazines (see Appendix).

Material to be swapped is always more appreciated by collectors who live near the locality where it has been found. They understand its desirability and from personal experience can estimate the time and effort that has gone into collecting it. But exceptionally good material is likely to find a market anywhere.

The rule is to bring to rock swaps only good, clean fossils, marked with as much information as is known about each specimen, including its scientific name, age, formation, the locality where it was collected and the date when it was found. Material neatly arranged in flat trays or boxes with paper collars around the specimens to keep them unbruised will attract the swapper's eye. Some swappers mount specimens on styrofoam blocks using a silicone rubber cement which holds them firmly but can easily be peeled off by the new owner. This allows the specimens to be packed tightly in a box without requiring wrapping. It is well to take several grades of specimens, however; some to be moved quickly to keep the swapping active without too much regard to value, or to give to junior collectors, and some to hold onto until highly desirable specimens can be had in exchange.

A canny swapper looks over other swappers' material with an eye for what he wants, then brings out his best material. He must learn, however, to say No when some charming child or seemingly pathetic oldster tries to cozen him out of a prize specimen, or when something that he does not need or want is pressed on him.

An amateur fossil collector, mindful that he collects what he needs for personal use, swaps with other amateurs, but he buys from dealers and does not attempt to profit from his material.

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    How to coat fossils in ammonium chloride smoke?
    4 years ago

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