FIG. 241.—Map of the gorge of the Zambesi River below the Victoria Falls (after Lamplugh).] =The repeating pattern in drainage networks.=—It is a characteristic of the joint system that the fractures within each series are spaced with approximation to uniformity. If the plan of a drainage system has been regulated in conformity with the architecture of the underlying rock basement, the same repeating rectangles of the master joints may be expected to appear in the lines of drainage—the so-called drainage network. Such rectangular patterns do very generally appear in the drainage network, though they are often masked upon modern maps by what, to the geologist, seems impertinent intrusion of the black lines of overprinting which indicate railways, lines of highway, and other culture elements. On river maps, which are printed without culture, the pattern is much more easily recognized (Figs. 242 and 243). Wherever the relief is strong, as is the case in the Adirondack Mountain province of the State of New York, individual hills may stand in relief between the bounding streams which compose the rectangular network, like the squared pedestals of monuments. Such a type of relief carved in repeating patterns has been described as “checkerboard topography.” [Illustration: FIG. 242.—Controlled drainage network of the Shepaug River in Connecticut.] [Illustration: FIG. 243.—A river network of repeating rectangular pattern. Near Lake Temiskaming, Ontario (from the map by the Dominion Government).] =The dividing lines of the relief patterns—lineaments.=—The repeating design outlined in the river network of the Temiskaming district (Fig. 243) would appear in greater perfection if we could reproduce the relief without at the same time obscuring the lines of drainage; for where the pattern is not completely closed by the course of the stream, there is generally found either a dry valley or a ravine to complete the design. If these are not present, a bit of straight coast line, a visible line of fracture, a zone of fault breccia, or the boundary line separating different formations may one or more of them fill in the gaps of the parallel straight drainage lines which by their intersection bring out the pattern. These significant lines of landscapes which reveal the hidden architecture of the rock basement are described as _lineaments_ (Fig. 82, p. 87). They are the character lines of the earth’s physiognomy.