bone chert

例句：

1. 1. The fossils found in the caveare evidence of ancient life on Earth.
   洞穴中发现的化石是地球古代生命的证明。
2. 2.The white color of the bone chert is due to its high calcium content.
   骨质石灰石之所以呈白色，是因为其高钙含量。
3. 3. Thelocal government has been workingon a plan to reclaimthe bone chert land fordevelopment.
   当地政府一直在努力计划将石灰岩土地重新开发用于建设。