With the expanding awareness of environmental needs during the past decade, the value of geologic information to urban and regional planning has become increasingly apparent. Earth materials in the form of rock and unconsolidated sediments provide a basis for our very existence. They yield building stone, coal, oil, gas, ground water, a wide variety of minerals, and sand and gravel, and we grow our crops in soils - all from a small portion of the earth's upper crust. Continued use of these mostly nonrenewable natural resources and increasingly complex economic and distributional problems have ushered in the era of shortages. Clearly, every effort must be made to plan future use and urban growth in such a way as to maximize efficiency and minimize waste. This calls for a cooperative approach to planning. Practical knowledge of hydrology, geology, soils, engineering, biology, botany, and economics can help planners to make judgements that will result in the greatest benefit to urban and rural communities alike. The maps presented here are to supply as much simple and direct geologic information for a particular area as is possible. These special geologic maps and their explanations were prepared after consultation with official representatives of Hendricks County, who outlined their then-current needs. The information contained in this report is not comprehensive, but it answers many practical questions posed at the onset of the study.