Geological and topographical maps, their interpretation and use, a handbook for the geologist and civil engineer . —Inlier in Glen Bally-emon, Co. Antrim. (1) Schist ;(2) Old Red Sandstone ; (3)sometimes affected by later Trias. (4) Cretaceous; (5) Ter-folds striking in a different tiary Basalt,direction, and in this way extremely complex outcrops are sometimes vary so widely in form that no general discussionof them is possible, but it may be well to remember that,where two anticlines cross, a dome-like structure with qua-qua-versal dip will be produced, while the intersection
Geological and topographical maps, their interpretation and use, a handbook for the geologist and civil engineer . —Inlier in Glen Bally-emon, Co. Antrim. (1) Schist ;(2) Old Red Sandstone ; (3)sometimes affected by later Trias. (4) Cretaceous; (5) Ter-folds striking in a different tiary Basalt,direction, and in this way extremely complex outcrops are sometimes vary so widely in form that no general discussionof them is possible, but it may be well to remember that,where two anticlines cross, a dome-like structure with qua-qua-versal dip will be produced, while the intersection oftwo synclines gives rise to a basin. It will be readily understood that symmetrical domesand basins produced in this manner are extremely rare innature, as folded areas offer great resistance to subsequentplication in another direction, the result being thatfractures usually occur. This resistance may be illus-trated by an attempt to bend a piece of corrugated iron atright angles to the corrugations. It frequently happens that folded areas are tilted bysubsequent movements, and the outcrops resulting from. Fig. 41.—Outcrop of a TiltedAnticline. 64 GEOLOGICAL AND TOPOGRAPHICAL MAPS the denudation of such tilted folds are usually curved inthe manner to be seen in Fig. 41. The various complicated forms of outcrop which mayarise in this manner may be illustrated by cutting sectionsof a piece of wood, showing rings of growth, in variousdirections, and are often well seen in polished pitch-pine desks and the like, where thetable-surface represents theoutcrops on the map and theends of the desk show thestrata in section. Repetition of Folding.— It has been frequently ob-served that when folding hasonce taken place along anaxis, there is a tendency forsubsequent movements totake the same line, and these successive movements maytake place in the same or in widely separated geologicalperiods. Should denudation have taken place in theinterval between successive movements of the fo
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