[Fig. 144]
Figures 145 to 148 are tented arches because of the angles formed by the abutting ridges at the center of the patterns.
[Figs. 145-148]
Figure 149 is a tented arch because of the upthrust present at the center of the pattern. The presence of the slightest upthrust at the center of the impression is enough to make a pattern a tented arch.
[Fig. 149]
An upthrust must be an ending ridge. If continuous as in figure 150, no angle being present, the pattern is classified as a plain arch.
