Old rivers like the Baraboo have wide flood plains and many wide curves called meanders. These sharp bends and twists can become so curved that a loop is formed, separated by only a narrow neck of land. The river eventually cuts across the neck, deposits sediment at both ends of the meander, and abandons it, forming an oxbow lake or slough. Over time these lakes fill with mud and silt. During the late 1800s and early 1900s, early settlers dug clay from the bottom of this slough and mixed it with sand and water to make bricks. The bricks were dried in sheds and fired in kilns heated by wood, sometimes requiring as much as 300 cords of handcut lumber. Many local buildings were constructed from this slough's clay.