How to Use this Guide

General philosophy of the Teacher-Friendly Guides™

This Guide is organized by regional geologic history because it helps make sense of local Earth science—Why does this place look the way it does? Why is this particular set of rocks, soil, landforms, water bodies, and local climate here? We recommend introducing geologic history into your curriculum early.

The idea of systems also runs through the Guide. Through systems we understand, for example, why geologic history controls where different types of rocks occur, helping us make sense of landforms and water bodies. Landforms and water bodies in turn influence local climate, and all of it influences life. Understanding a few essentials of geologic history and Earth systems allows us to make sense of the world around us.

Please incorporate ideas from the Guide into your existing curriculum. This Guide is a resource rather than a curriculum itself.

Understanding real-world Earth science is a lifelong learning experience. Don’t be intimidated by rocks that you don’t recognize, fossils with long names, or complicated weather patterns. Enjoy learning alongside your students and show that enjoyment.

A National Series of Guides

Region covered in guide.

This Guide is one of seven covering the United States. There are also two Teacher-Friendly Guides™ to evolution, one focused upon bivalves and another focused on maize genetics. To learn more, visit, a website of the Paleontological Research Institution.

To download individual chapters for printing, click “Downloads” on the chapter menu to the left.

To purchase a printed grayscale copy, visit “Publications” at the Paleontological Research Institution website. Images in the printed version, which are in grayscale, are available in color in the digital versions.

Design of the Guides

Subregions in this guide.

Most chapters in this guide divide the Midwest into three broad regions, each of which has a different geologic history and thus varies in rocks, fossils, topography, mineral resources, soils, and Earth hazards. The Geologic History chapter explains the history of all three within the context of Earth history. Chapters on climate and glaciers are not divided by region because these tend to be driven by processes at broader geographic scales.

Big Ideas icon

Each Guide begins with five cross-cutting Big Ideas of Earth science. These have applications across the curriculum. Deep study of specific Earth science sites gives context and meaning to these most fundamental ideas, and in turn understanding these ideas facilitates a lifetime of making sense of Earth processes anywhere.

Fieldwork icon

Each Guide ends with a chapter on fieldwork—even from the classroom. You and your students can begin to interpret the Earth science in your area, and bring back photos and data to re-visit your field sites—using “virtual fieldwork”—throughout the year. More information is available at

Use the color geologic map as a reference tool while you read this Guide. The map is on the back cover of the printed Guides and available as a downloadable graphic on the website.


You do not have to read this Guide from front to back! Each chapter is written to stand alone. Main concepts are repeated in more than one chapter. In this way you can use read just what you need, in any order, as you approach particular units through the school year.

The chapters are cross-referenced, should you need to find more information about a particular concept or region. Bold-faced words are defined in a separate glossary, with selected words defined in chapter side bars.

For Further Information...

At the end of each chapter are lists of resources specific to that topic. There are lists of national and state-based resources, many of which cover multiple topics, at the end of the Guide.