Histories of techniques are seldom written and when written commonly are boring, for there is a dearth of dramatic developments to recount or great practitioners to extol. Study of the preparation of fossils is no exception to this generalization, and it is hard to do more than compile anecdotes which may not even form a coherent theme. On the other hand, this approach could be appropriate, for the techniques of preparation are largely spread by word of mouth and in the main consists of improvement by small increments. Paleontological and museum journals devote a bit of space to preparation techniques, but the field does not have a rich literature and more people still learn by doing than by reading.

In the purest sense, all paleontology begins with collecting fossils in the field. The field is a generic term that includes any place where interesting rocks crop out at the earth's surface. What makes those rocks interesting depends on many things, frequently related to making a geologic map of an area and ultimately unravelling its geologic history. The geologist uses superposition of strata to get started with the task, but sooner or later one wants to know the ages of the formations and their correlation with similar rocks in the next county, state or exotic tectonic terrane. Fossils are the answer.

Most of the nonmineralized organic material that enters the sedimentary record is either destroyed or preserved as an amorphous component. Preservation of nonmineralized plant and animal parts as recognizable fossils depends on exceptional conditions in the depositional environment or unusually resistant material (e.g. wood; spores and pollen; chitinous exoskeletons). Thus, one of the first lessons learned by each student of the fossil record is that it is strongly biased toward taxa with mineralized parts.

Preparation of fossils, as well as their subsequent study and illustration, can be accomplished utilizing a broad spectrum of techniques. Even though some of the procedures require nothing more complex than hammer and chisel, such work can be extremely demanding. Regardless of the techniques employed, the worker must exercise extreme care and patience in performing this work. A fossil specimen simply cannot be replaced!

Recent medical literature has pointed out the health hazards associated with industrial wastes and by-products; however, little emphasis has been placed on the dangers inherent in scientific laboratories. These hazards range from direct contact with toxic chemicals and vapors to exposure to ionizing radiation. The damage may be acute or chronic; the effects temporary or residual. What follows is a summary of the common hazards, the basic management of laboratory trauma, and guidelines to prevent injury. The individual preceding chapters also contain safety information relative to the specific lab techniques discussed.

This bibliography contains works, published from 1964 through late 1988, on paleontological techniques. It is intended to supplement, in part, the earlier bibliography by Kummel in Kummel and Raup (1965). The techniques are those used for vertebrate and invertebrate paleontology, including techniques for some protistan groups, but publications specifically on palynological or paleobotanical techniques are not included. The works included generally, but not entirely, reflect the areas covered in the other chapters of this book. Citations were obtained from many sources, notably the Bibliography and Index of Geology. Most publications cited were examined.

Microfossils are most profitably studied as discrete specimens that have been freed from the enclosing rock matrix. Techniques for separating microfossils from matrix and from matrix residues are numerous and relatively simple. Choice of a procedure will depend on the types of microfossils sought, their composition, and the laboratory facilities available. Our own work deals mostly with phosphatic microfossils (conodonts), which are chemically resistant and may be freed from rock matrix and concentrated fairly easily. Calcareous microfossils, such as foraminifers and ostracodes, may be separated and concentrated from relatively unconsolidated sediments rather easily, but freed from some other rock types only with considerable effort (Lethiers and Crasquin-Soleau, 1988), inadequately, or not at all. Many of the laboratoryprocessing techniques for phosphatic, calcareous, and siliceous microfossils are the same. We have not included techniques (e.g., thin-sectioning, preparation of latex replicas, or slabbing) for studying these microfossil groups in rock matrix.

The term palynomorph generally includes the spores of lower vascular plants (isospores/homospores, and megaspores), prepollen, the pollen of gymnosperms and angiosperms, dinoflagellates, acritarchs, fungal spores, and algal remains. Chitinozoans, scolecodonts, and foraminiferal inner tests also are concentrated by palynological processing techniques, and some palynologists therefore include them as palynomorphs. These processes isolate any silt-sized or sand-sized acid-resistant organic-walled particles, however, and also will concentrate foraminiferal inner tests leaf cuticle, vascular debris from plants, chitinous insect parts, etc., which usually are not considered palynomorphs. All of the above are recovered, definition notwithstanding.

The described techniques for extraction of microfossils are directed primarily at the extraction of calcareous microfossils from various types of limestone, although the same techniques may beused for some sandstones and shales. The equipment needed is not complicated; the most obvious is a good binocular microscope with a working distance of three or more inches, to allow manipulation of the rock from which the specimens are to be extracted. The magnification required depends on the size of the specimens, but should go up to at least 80x. Other essential tools are a pin vise with a chuck which will hold an ordinary steel sewing needle and a rotary dental machine or other grinding device which will accept a small thin carborundum wheel. The latter is useful for sharpening needles as well as for cutting specimens out of the rock. An additional useful item is a percussive device such as a mechanical engraver fitted with a chuck which will hold an old fashioned steel phonograph needle. This instrument is described in detail by Palmer (this volume, chapter 20). A dish of water and a fine (00000) camel's hairbrush are necessary to move the specimens, once freed, to a slide or other receptacle. A rock trimmer is useful for reducing large blocks of fossiliferous rock into pieces that can be handled under the microscope, although with some collections this can be done with a hammer and cold chisel. Some paleontologists prefer to crush their samples and then pick through the chips to find specimens; however, this technique tends to break spines and frills from highly ornamented forms and is not recommended unless the microfauna is known to consist mostly of smooth species. Most of the equipment mentioned above can be found in catalogs such as that of the Edmund Scientific Co., 101 E. Gloucester Pike, Barrington, N.J. 08007.

Until the mid-1960's, procedures for studying shell microstruetures were laborious and, for many purposes, unsatisfactory. Depositional surfaces were observed with binocular microscopy, and shell material was embedded in various media, sectioned, mounted on a glass slide, and observed with ordinary light and polarized light microscopy. These procedures revealed the major microstructural organization of shell layers and their optical crystallographic properties, but they provided little information regarding what is now termed shell ultrastructure. Nevertheless, these techniques provided the basis for a number of important pioneering works on molluscan shell microstructure between 1921 and 1967.

Thin sections are slices of rock, mounted on glass, that are ground thin enough to transmit light. This allows microscopic examination of crystals, grains, fossils, and rock fabrics. Thin sections are of special value to three groups of paleontologists: 1) taxonomists studying groups whose classification rests on internal features or skeletal fabrics (such as foraminifera, stromatoporoids, some coelenterates & bryozoa, etc.), 2) paleoecologists interested in reconstructing biofacies from sand-size skeletal fragments, and 3) those interested in diagenesis of fossils and initial mineralogy. Almost anything can be made into a thin section, although metals and certain opaque minerals will not transmit light.

A large variety of techniques and chemicals are available to aid the study of fractured and otherwise friable material. Many of the techniques are quite complex, well beyond what someone might wish to do for a once-in-a-while project. This paper will review a series of methods that range from simple to the very forceful and complex techniques needed for specimens with very low permeability. However, it will empasize both the simpler methods and those that have been published since the classic works of Bouma (1969, especially p.1–139, 260–290, & 377–378), Stanley (1971), and Allman and Lawrence (1972, p.73–92).

Acetate peels are replicas of etched surfaces embedded in sheets of cellulose acetate. These replicas are usually so detailed that the fine structure of shells and various sedimentary rocks can be easily studied under a light microscope. Because these peels can be quickly and easily produced, the procedure is now commonly used in most geologic laboratories.

Serial sectioning (also referred to as serial grinding) is used to investigate the internal structures of three-dimensional (rock or fossil). In this process series of sections are ground or cut in sequence through a specimen to reveal its internal structures. The specimen is ground down against an abrasive surface (e.g., abrasive powder on a sheet of steel or a rotating diamond wheel on a lathe) or cut with a saw blade. The details of each section can be recorded by drawing or photography. A permanent record of each surface can be made by taking acetate peels and mounting them in glass slides (Wilson and Palmer, this volume, Chapter 13). Serial section information can be digitized and reconstructed in three-dimensions using computer techniques (Chapman, this volume, Chapter 15).

The importance of serial sections for the analysis of the morphology of fossil organisms has been stressed by a number of authors (e.g., Westbroek, 1967, 1969; Cooper, 1983; Sandy, 1986, this volume, Chapter 14) because they provide a way to visualize the three-dimensional structure, both internal and external, of specimens that cannot be studied in other ways. The importance of internal structures for the taxonomy of many groups (e.g., the brachidia of brachiopods; Westbroek et al., 1976; Cooper, 1983) makes the study of serial sections imperative in many cases for proper taxonomic identification.

There are at present two techniques that use X-rays to show internal structures, both are in common use in medicine. The first technique is essentially a photographic method (for extensive description see Quinn and Sigl, 1980). The second (Cat scan or Computer Tomography) computes a section from many pictures taken by a thin, fan shaped X-ray beam. X-rays are a form of electromagnetic radiation with a wave length 10,000 times smaller, and energy 10,000 times greater, than visible light. They are generated in a high-vacuum tube where electrons are produced by a heated cathode and are shot at high electromotive force (30 to over 100 kilovolts) at the anode where most of the energy is converted to heat; only a small fraction is given off as X-radiation.

Scanning electron microscopy has long been used by paleontologists for the detailed morphological study of fossil organisms. Often, however, as in studies of growth or diagenesis, the researcher is also interested in the chemical composition of the specimen. Traditional methods of chemical analysis, such as “wet” chemistry or atomic absorption, require destructive preparation (crushing, grinding, solution) and provide only bulk chemical analyses; there is no measure of the spatial distribution of elements.

Hand-held mechanical tools used in paleontology range from Jackhammers to high speed grinders. They operate by impact or rotary motion and are powered by air, gasoline, or electricity. These labor-saving devices are used in addition to, not as replacements for, hand tools such as awls, pin vices, chisels, and picks for the collection of and the removal of matrix from fossils.

The extraction of fossils by the use of chisels, hammers, and picks is probably the oldest of the methods dealt with in this volume. One must also admit that it may be the most tedious and time consuming method considering the more recent applications of power tools. Yet, exacting as it is, one has only to visualize the exquisite craftsmanship displayed in the sculptures of antiquity to realize the potential of these hand tools.