缙云县古官道民居的文化价值研究
Study of Culture Value of Civilian Residence of the Old Official Road in Jinyun County
豫西杜关锰结核产于华北地台南缘，中元古界官道口群龙家园组下段。
The manganese nodules of Duguan occur at the bottom of Longjiayuan formation in Guandaokou group at the southern margin of North China platform .
古官道