Archaeology Case Studies
Lime Kiln Investigation - Harrison-Crawford State Forest
The lime industry developed along the limestone cliffs in southern Indiana during the 19th century; although the process of transforming limestone to lime dates back over 2,000 years. Limestone was burned in kilns, forcing the carbon dioxide from the rock and creating a powdered or lumpy substance called quicklime. This lime was spread on agricultural fields or mixed with other ingredients to form mortar, plaster, whitewash, etc.
Several lime kilns have been identified within the Harrison-Crawford State Forest in southern Indiana. These features represent pit kilns, into which alternating layers of wood and stone would be piled and burned. Pit kilns were typically used to create a lower quality lime to spread on agricultural fields.
A survey was conducted in 2004 to record all known lime kilns within the Harrison-Crawford State Forest. Interviews with local residents and field surveys were conducted in an attempt to locate these features. As a result of this investigation, three separate areas were documented containing approximately two dozen kilns.
Kilns were typically discovered grouped together along the side slope of a ridgeline below the limestone cliffs, where the quarries for the kilns were located. Groupings generally consisted of six or more kilns in a rough linear formation.
The study continues to grow as previously undocumented kilns are identified and added to the inventory. Further studies of the lime industry in the State Forest are planned in hopes of identifying the specific dates that the kilns were in operation as well as a comprehensive understanding of the lime industry during the 1800s.
Artifacts and Results
Several of the sites retained cut limestone blocks, some of which are still stacked where they were left 100 years ago, and hydrated quicklime within the kiln structure. Slag, a by-product from the burning process, was also identified during the survey of the lime kilns.
Studies of these items can help to identify the stage in the burning process each kiln was in at the time that the site(s) was abandoned. Further investigations may also help to reveal more detailed information on the lime industry in Harrison and Crawford Counties.
Nearly two dozen lime kilns have been identified within the Harrison-Crawford State Forest. Investigations on these sites and similar archaeological sites indicate that the kilns were in operation during the mid 1800s to early 1900s. By the turn of the century the lime industry had declined due to advances in artificial cement, which was stronger and harder than mortar created from quicklime, and other lime based products.
Case Study Credits
A. J. Ariens, Archaeologist
Indiana State Division of Forestry