Figure 144 is a tented arch combining two of the types. There is an angle formed by ridge _a_ abutting upon ridge _b_. There are also the elements of the type approaching a loop, as it has a delta and ridge count but lacks a recurve.
Figures 145 to 148 are tented arches because of the angles formed by the abutting ridges at the center of the patterns.
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.
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.
Figures 151 to 153 are plain arches. Figure 154 is a tented arch.
Figure 155 is a plain arch because it is readily seen that the apparent upthrust A is a continuation of the curving ridge B. Figure 156 is a tented arch because ridge A is an independent upthrust, and not a continuation of ridge B.
Figures 157 and 158 are plain arches. Figure 158 cannot be said to be a looping ridge, because by definition a loop must pass out or tend to pass out upon the side from which it entered. This apparent loop passes out upon the opposite side and cannot be said to tend to flow out upon the same side.
In figures 159 and 160, there are ending ridges rising at about the same degree from the horizontal plane.
Figure 159, however, is a plain arch, while 160 is a tented arch. This differentiation is necessary because, if the first pattern were printed crookedly upon the fingerprint card so that the ending ridge was nearer the horizontal plane, there would be no way to ascertain the true horizontal plane of the pattern (if the fissure of the finger did not appear). In other words, there would be no means of knowing that there was sufficient rise to be called an upthrust, so that it is safe to classify the print as a plain arch only. In figure 160, however, no matter how it is printed, the presence of a sufficient rise could always be ascertained because of the space intervening between the ending ridge and the ridge immediately beneath it, so that it is safe to classify such a pattern as a tented arch. The test is, _if the ridges on both sides of the ending ridge follow its direction or flow trend, the print may be classified as a plain arch. If, however, the ridges on only one side follow its direction, the print is a tented arch_.