Ash falls an Volcanic conduit pyroclastics 岩床 Volcanic neck with Volcano Lava fld 岩墙 radiating dikes 岩株 岩基 FIGURE 4.16 Basic extrusive and intrusive igneous structures.Notice that dikes cut across layers of country rock,but sills run parallel to them.Batholiths are the largest forms of plutons. 岩墙 岩床 岩基 岩株