Introduction
This field guide is divided into three sections, namely minerals, rocks (including meteorites and tektites) and fossils. Each section comprises an introductory part, which is illustrated by line drawings, and a descriptive part, which is illustrated by line drawings and color photographs. The introductory sections include the minimum basic information required to follow the descriptive sections adequately, while the descriptive sections, for ease of reference, are always arranged so that photographs and accompanying text are closely adjacent.
To make the best use of the book the contents page and index should be used freely. The contents list will enable you to turn quickly to the appropriate section of the book, whereas if a tentative identification has been made, then reference to the index will immediately direct you to the relevant page. The index includes not only the names of specific minerals, rocks and fossils, but also technical terms which are used in describing them. By consulting the index you will be referred to the page on which the term is defined, and possibly illustrated.
The stratigraphical column is given on page 328, and will be a particularly valuable reference for collectors of fossils.
How to collect in safety
Before setting out to collect it is most important to give thought to, and to take such precautions as would ensure, one's personal safety and preserve the interests of others. Excellent advice is given in Planning for Field Safety, a reference published by the American Geological Institute. All those who contemplate geological fieldwork are urged to obtain a safety guide and to follow its advice.
The basic equipment required to collect is a hammer, chisel, notebook and pencil, felt-tipped pen, wrapping materials and a bag. The usual geological hammer has a square head and a chisel edge, which is particularly useful for splitting rocks when looking for fossils. Do not be tempted to use any other kind of hammer. Geological hammers are specifically tempered and others are likely to splinter when hammering, and metal splinters could damage the eyes. A steel chisel is sometimes required to prize open rocks which resist hammering, or for carefully breaking specimens which might be damaged by blows from a hammer. When hammering be very careful indeed of flying splinters of rock. Protective goggles can be obtained and should always be worn. Specimens should be carefully numbered; use either a felt-tipped pen or tape on which a number can be written. The exact locality from which the specimens were collected should be recorded in the notebook. Specimens should always be wrapped in plenty of newspaper in order to prevent chipping or scratching, and small or delicate specimens are best carried in a small box, such as a match or cigar box. If a large collection is to be made, or if long distances are to be walked, then a stout backpack is the most suitable kind of bag to have.
The best places to collect minerals, rocks and fossils are usually quarries, cliffs, road cuttings and mine dumps, but any outcrop of rock may prove fruitful. It should be borne in mind that rock outcrops are potentially hazardous and appropriate protective clothing should be worn. In addition to the goggles mentioned above, a helmet of approved design gives protection against head injuries. It is usually mandatory to wear a helmet in quarries. Injuries can also result from rock falling on the feet. Boots, rather than runners, or other soft footwear should be worn in the field, and those with protective toecaps offer the best protection. Particular care is needed, however, when collecting near quarry faces or from the foot of cliffs, and permission must always be sought if it is intended to collect from outcrops on private land. An increasing number of sites in Britain are being designated as Sites of Special Scientific Interest (SSSI), and are protected by law. Collecting from these sites may be restricted or forbidden: it is necessary to check in advance. Remember to take care and precautions if you intend to do field work on your own, and always tell someone of your intended route before setting out.
Geological maps, sometimes on a large scale, are available for most parts of the world, and they show the distribution and geological ages of the different rock types. This information should indicate where fossils are likely to be found, and where it is probably best to look for minerals, or for interesting rock types. If there is a museum in your area, a visit may well be worthwhile. Many museums not only have exhibits illustrating the geology of their vicinity, but they also usually have displays of minerals, fossils, and sometimes rocks, which will help you to 'get your eye in', and give you some idea of what is to be found in your neighborhood.
Housing a collection
A collection is best kept in a cabinet of shallow drawers, with the specimens placed in individual cardboard trays. Under no circumstances should specimens be placed one on top of the other. Each specimen should have its own label giving details of what it is and where and when it was collected. A number should also be firmly glued to each specimen, and a corresponding entry made in a notebook, card index, or in a computer giving details such as name and locality, and any other relevant information. This additional entry is a safety precaution against accidental loss of, or damage to, the label attached to the specimen.
The system followed in this book will prove a helpful and useful guide in arranging specimens, though there are, of course, other systems which you may prefer to follow. Mineral specimens, in particular, look their best when they are clean. To remove loose dust and dirt first take off the label, then immerse tne specimen in clean water to which a little detergent has been added, and lightly scrub it with a soft brush. This should not be done, of course, with specimens which are soluble in water, or with very delicate material.
Further reading
Although in the introductory sections of this guide, outlines of the subjects of mineralogy, petrology (the study of rocks), and paleontology (the study of fossils) are given, it is obviously not possible in a single volume to do justice to these subjects. Although something like 600 specific types of mineral, rock and fossil are described in the following pages, there are many other types which, for reasons of space, cannot be included. To help readers who would like to widen their knowledge, a list of recommended books is given on page 329. It would also be useful to include a list of the available geological maps and guides of particular areas, but such a list, if it is to be comprehensive, would need to be very long indeed. To find such maps and guides we suggest that you enquire at your local library.
For the real enthusiast there is no substitute for joining a geological society. Most countries have such societies organized on a national basis, but there are also local societies which cater mainly for the enthusiastic amateur, and which often have geological libraries, and organize field excursions to good collecting localities.
