News Release, Kansas Geological Survey, Feb. 24, 1999
The new map, by Survey geologist James McCauley, shows the age and type of rocks at the earth's surface. Geologic maps are used in a variety of construction and environmental projects, and provide clues about an area's potential for groundwater, minerals, and other geologic resources.
"As urbanization continues from Kansas City into Leavenworth County, the geologic information displayed on this map will be especially helpful for land-use planning," said McCauley.
The new map of Leavenworth County shows that the bedrock in much of the county is composed of limestones and shales that were deposited in the Pennsylvanian Period of geologic history, about 300 million years ago. Smaller amounts of sandstone, and a few layers of coal, are also found in the county.
Hills in much of the western half of Leavenworth County, for example, are capped by rocks that geologists have labeled the Oread Limestone, the Kanwaka Shale, and the Lecompton Limestone. One of the common rock layers in central and eastern Leavenworth County is the Stranger Formation, named after Stranger Creek. The Tonganoxie sandstone, a rock layer in the Stranger Formation, was deposited in the valley of a river that drained the area during the Pennsylvanian Period.
Rocks in much of the rest of the county were deposited more recently, about 600,000 years ago, when glaciers moved into the northeastern tip of the state. In Leavenworth County, the glaciers left behind boulders, cobbles, and other rock debris that is commonly referred to as "glacial drift." Along the Missouri River, in the northeastern part of the county, the map shows thick deposits of loess, a silty soil that also resulted from glacial activity.
While geologists have studied the geology of Leavenworth County since the 1860s, this is the first detailed geologic map of the county to be published. It is one in a series of new county geologic maps being developed and published by the Survey.
The map was drawn at a scale of 1:50,000, so that one inch on the map equals about 0.8 miles of actual distance. In addition to geology, the map shows highways, county roads, railroads, towns, creeks, ponds, lakes, and other features, such as the Fort Leavenworth military reservation.
Copies of the map are available for $15.00, plus $3.00 postage and handling, from the Kansas Geological Survey (785-864-3965), 1930 Constant Ave., Lawrence, KS 66047. Kansas residents should add 6.9% sales tax.