“岩层”造句

较老的岩层渐渐风化.
The older strata gradually disintegrate.

岩层中有证据表明，该地区在15,000年前曾经非常干旱。
Contained within the rock strata is evidence that the region was intensely dry 15,000 years ago.

这一岩层中有大量燧石.
This layer of rock contains a lot of flint.