Type lines are not always two continuous ridges. In fact, they are more often found to be broken. When there is a definite break in a type line, the ridge immediately outside of it is considered as its continuation, as shown by the emphasized ridges in figure 13.
[Fig. 13]
Sometimes type lines may be very short. Care must be exercised in their location. Notice the right type line in figure 14.
[Fig. 14]
When locating type lines it is necessary to keep in mind the distinction between a divergence and a bifurcation (fig. 15).
[Fig. 15]