What are the corduroy roads?

Corduroy roads are roads that are built with logs or poles placed across swampy or unstable ground. This type of road was used by wheeled vehicles and horses. Cattle and herds of pigs or sheep were not allowed on the road because of spaces between the logs and poles. Sometimes hewed or sawn lumber was used in the corduroy road. Look up some of the books about the old days written by Eric Sloane.