Contained within the Atlas of Canada's Reference Map Series, 1961 to 2010, is a general reference map of the continent. The map shows countries by colour. It also shows the individual states, provinces and territories of the United States and Canada. There is no differentiation of the populated places by size, but this is visually indicated by means of varying townstamp size and label size. The map shows roads and railways, but without any size classes for them. The map was superseded by newer versions of MCR 31 in the 1990's and beyond. Data for the 1971 map is as of the mid-1960s.