News Release, Kansas Geological Survey, Jan. 24, 2002
The map, based on field work by retired U.S. Geological Survey geologist William D. Johnson, Jr., depicts the age and type of rocks at the earth's surface. The map also shows roads, towns, rivers and ponds, railroads, and other features.
Because geologic maps show the rock formations likely to be encountered at a particular location, they are useful in construction, in understanding soils and agriculture, in searching for water and mineral deposits, and in a variety of engineering and environmental uses.
Anderson County is in the Osage Cuestas physiographic region of the state, an area where the bedrock is predominately limestones, sandstones, and shales. These rocks were deposited during the Pennsylvanian Period of geologic history, about 300 million years ago. In addition, much younger silts, sands, gravels, and other geologic materials were deposited along the rivers and streams in the region,
The map shows a number of areas where the hilltops are covered by gravels largely composed of chert (or flint). These deposits are unusual because the rocks are rounded, an indication that they were deposited by streams. In this area, however, the gravels generally occur on hilltops, high above present day streambeds, suggesting they were deposited by ancient rivers. A number of small pits have been dug to mine these gravels, which are used on roads and for other construction purposes. Quarries have also mined the county's limestone for crushed rock. Both types of quarries are shown on the map.
The map, produced in full color, is drawn at a scale of 1:50,000, so that one inch on the map equals about 3/4 mile of actual distance. The map measures about 36 by 44 inches.
Copies of the new map are available from the Kansas Geological Survey, 1930 Constant Ave., Lawrence, KS 66047 (or phone 785-864-3965). The cost is $15.00, plus $4.00 for handling and postage. Kansas residents should add 6.9% sales tax on the cost of the entire order. More information about the maps and other Survey products is available at the Survey's web site (www.kgs.ku.edu).