Discusses the need to take into account the effects of arrested fractional crystallization in the petrographic classification of volcanic rocks containing plagioclase phenocrysts. Describes the development and use of a computer program to accomplish this task graphically. (TW)

Describes how the limitations of the built-in graphics capabilities of spreadsheet software can be overcome by making full use of the flexibility of the grahics options. Uses triangular plots with labeled field boundaries produced using Lotus 1-2-3 to demonstrate these techniques and their use in teaching geology. (CW)

Describes how the graphics capabilities of the Apple Macintosh computer can be used in geological teaching by customizing fill patterns with lithologic symbols. Presents two methods for doing this: creating a dummy document, or by changing the pattern resource resident in the operating system. Special symbols can also replace fonts. (TW)

Describes a computer-assisted oil exploration and production game for students involved in a short course in petroleum geology. Outlines the game and its procedures, and provides sample structure maps generated by the computer in the course of playing the game. (TW)

Describes a microcomputer program that simulates the pattern of evolution and produces clade diagrams and summary statistics. Allows users to vary the odds affecting the fate of a species. (TW)

Reviewed are four computer software packages: "Minerals Data Base"; "Canvas 2.1," a graphics program for producing technical illustrations; "Glossary of Geology Speller"; and "PCUSA," which produces maps and statistical diagrams of the United States. Hardware requirements, functions, cost and availability…