Lyle Retz Memorial Woods is a 49-acre preserve featuring a rugged forested area in the Paleozoic Plateau landform region. It is located 4.5 miles southeast of Elkader in Clayton County. The area was purchased in 1965 from the Kopp family by the Iowa chapter of The Nature Conservancy. The area was dedicated as a biological and geological state preserve in 1980 and named in memory of Lyle Retz, a key member in pursuing the purchase of the property. One of his sons wrote, “A piece of native timber, regarded as worthless by some, yet priceless by dad, unspoiled, left as God made it, is a living memorial more grand, more meaningful than any granite or marble stone could be. This has been a great tribute.” The preserve displays the dissected terrain typical of the Paleozoic Plateau in northeast Iowa. A deep ravine cuts through the eastern portion of the preserve. Picturesque limestone ridges and chimneys located along the eastern edge of the preserve belong to 450-million-year-old sedimentary rock of Ordovician age. Massive blocks of limestone slumped from nearby rock outcrops are covered with lush expanses of walking ferns, mosses, liverworts, and lichens.