Hearths are areas, generally relatively shallow, where people were cooking. Earth ovens are deeper pits. Both are usually lined with stones to hold the heat. Earth ovens might have been used to roast meat, corn, or tubers. A fire would be built in the bottom of the pit, and then the food added. The whole might have been covered with wet grasses or leaves or a thin layer of soil, and then another fire built over the top to cook the food.