The primary land mass is represented as one continuous unbroken land mass extending from the Isthmus of Panama to Behring Strait, and is itself divided into two main slopes. The secondary land mass is likewise divided into two slopes; it is also separated by the St. Lawrence River basin into two parts, viz., the northern or Labrador land mass, and the southern or Appalachian land mass. [Fig. 63] is drawn to represent the drainage, or principal river basins; as, the Mississippi, Mackenzie, St. Lawrence, and Saskatchawan basins, and the Hudson Bay river system. In drawing small maps on paper it is necessary to trace the rivers with a fine pencil point. For very large maps, four of five feet long, spaces may be left, but great care should be taken to keep them as narrow as possible, so as not to exaggerate the width of the rivers more than is necessary. [Fig. 64] is drawn in more detail and the great political divisions are marked upon it. On the blackboard map these divisions may be marked with colored chalk, and should follow the contour of the surface as closely as possible.
For the teacher who wishes to rapidly chalk model a map for immediate use in the class, the following hints may be of service:
Plan to draw the continent in its proper proportions within a given space. Imagine that you see it as already drawn. Commence with the region best known or understood, and draw as you mentally travel, to the north, south, east or west. It may be that you will begin with the great depressed regions, in which case draw the ascending slopes and crowning altitudes as you mentally picture; or if the great highlands or water partings are fixed upon as a starting-point, the descending slopes should be drawn to the line of meeting of other slopes, or to the sea level.
Break the line to indicate broken or uneven surface. You will do this naturally, however, if you have in mind the picture of a broken surface.
63
Keep the river basins definitely in mind, and the character of streams and rivers: the character also of the land structure; whether it is rocky or alluvial; sharp or hard, or soft and yielding. Knowing that line represents direction, and having a clear and distinct picture in mind of the real country with its surface features, it will be an easy matter to draw or represent it. Understand, as has often been said, that the delineator is drawing from his own mental image of a map, and not copying the work of another. In the latter case no instructions are necessary, as the practice is of no educative value, and should be persistently discouraged.