The beginning collector is usually content to know if his specimen is a clam or a snail or a fern or a palm leaf. But as the collection grows, it becomes increasingly desirable to know the scientific name of each [fossil].
When he starts to identify fossils it may be helpful to show them to a geology teacher if a college or university is nearby. Most teachers are glad to be of help and will probably have similar specimens in their own collections. As all colleges do not have geology departments, a list of institutions with geologists on their faculties is included at the end of this section of the handbook ([p. 27]). In addition, many of the science teachers in the public schools are familiar with fossils and can give helpful suggestions as to how to classify material.
Museums are also good places from which to get help. If the museum has a geological collection, it will be most helpful to compare specimens with the fossils in their collections and to ask the museum personnel for advice. In addition to the above sources of information, local professional geologists are usually familiar with the geology of the local area and the paleontological literature of the region.
Possibly local librarians can recommend books, encyclopedias, or other publications that will be of help. Members of a local [rock] and mineral club, if one is available, are another source of information. Many times these collectors can pass along good ideas and tell exactly which books to consult.
After books or journals describing the fossils of the area have been located, the collected specimens should be closely compared with any illustrations that are shown. Each [fossil] should be examined carefully, its more characteristic features noted, and it should again be compared with the illustrations and descriptions in the book. The [phylum] or class to which the specimen belongs should be determined first. For example, the genus and [species] of a certain fossil may not be known, but it looks like a snail and accordingly it is named a [gastropod] (for class Gastropoda, the snail class), and this is, at least, a start in determining the scientific name of that particular fossil. The descriptive material in the text of each reference will usually point out the more detailed features which will be diagnostic of the genus or species.
The illustrations and descriptive material in this publication will also be of considerable help in identification. Many illustrations of the more common invertebrate fossils have been included, but the publication was not designed primarily for use in [fossil] identification. Rather, it is intended to guide the amateur or student who is interested in fossil collecting, and to furnish suggestions as to how collecting may be more effectively pursued.
USE OF IDENTIFICATION KEYS
[Fossil] identification keys may be useful in helping the beginning collector identify specimens. The collector compares a fossil with the key description and eliminates those characters that do not fit the specimen.
The key used in this handbook is based primarily on [symmetry]—the orderly arrangement of the parts of an object with reference to lines, planes, or points. The shape of the shell or body, presence or absence of coiling, and presence or absence of body partitions are also useful criteria in identifying fossils. To use the key the beginner should know something about symmetry. Two major types of symmetry are used in this key.
1. [Radial symmetry]—the symmetrical repetition of parts around an axis. This is the [symmetry] of a wheel, and any vertical section through the center of the object divides it into symmetrical halves ([fig. 4]a).
2. [Bilateral] [symmetry]—the symmetrical duplication of parts on each side of a plane ([fig. 5]). The plane divides the object into two halves that are mirror images of each other. This is the symmetry of a plank.