标准号:IS 7422 Pt.2-1974
发布日期:1975/8/1 12:00:00
实施日期:1999/12/31 12:00:00
适用范围: This standard ( Part II ) covers symbols for igneous rocks for use in geological maps, sections and logs of bore holes, test pits, exploratory drifts and shafts for river valley projects. Rock types covered in the standard are restricted to those commonly met with in engineering practice.