Through mapping, the authors propose that between the Wutai Group and Hengshan gneissic complex there exists a gneiss layer which still belongs to strata and its mapping indicator is set up.

• 经过填图实践，总结出地层与片麻岩体之间存在着仍属地层范畴的片麻岩层这一无序岩石地层单位，并建立起它的填图标志。