Native Americans followed a lunar cycle of 28 days. Years were not numbered but referred to a "winters" and records were kept with a pictograph showing a major event of a particular year (i.e "The year everyone died of smallpox, The year when Yellow Hair was killed, etc.)People went out and hunted food or gathered food and then did other stuff until they need to go out for food again so the concept of the "week" and a day of rest seems to have developed in the Old World after the development of agriculture and the domestication of animals bringing about the rise of "specialists" like boot maker, carpenter, etc., creating a need for a "rest" day, possibly a "market" day when everyine gathered for the exchange of goods. It's all more complicated than this, or course.