I grew up near what is now called Gap Cave (formerly Cudjo’s Cave) in Cumberland Gap, Tennessee. (Sidenote: if you’re ever in that area, the National Park Rangers give a fantastic 2 hour guided tour). It was said that Gap Cave was used in Civil War times as a hospital. Caves being a natural choice when choosing shelter, these tips on how to construct a half-cave shelter come from “Shelters, Shacks, and Shanties” by D.C. Beard, 1914.
There is a time and place for making temporary camps. When the situation has changed quickly or you just took the moment to seize the day, these tips on sheltering may come in handy from “The Way of the Woods, A Manual for Sportsmen in Northeastern United States and Canada,” by Edward Breck, 1908.