Of,belonging to,or being the geologic time,system of rocks,and sedimentary deposits of the sixth period of the Paleozoic Era,characterized by the development of coal-bearing rock formations.

 
  • 宾夕法尼亚纪的,宾夕法尼亚系的属于、有关或是古生代第六纪晚石炭纪指地质年代或岩石系中含煤岩层的形成发展期的。
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