The "repository for dung" was designed to compost animal manure and a variety of organic materials to "cure" into fertilizer for use in the nearby gardens and orchard.  The building illustrates George Washington's dedication to finding ways to increase the fertility of his soil and to convert Mount Vernon into a model of progressive farming.  The original 31 X 12-foot, open walled structure was built in 1787 and was reconstructed in 2001.  Archaeologists revealed remnants of the brick foundation walls along with the virtually intact cobble stone floor, and they have been incorporated into the reconstructed building.  Washington's dung repository is the first known structure in the United States devoted to composting.