packstone

例句：

1. 1. The riverbed is covered in smooth packstones.
   河床覆盖着光滑的卵石。
2. 2.The path was paved with smooth packstones.
   这条小径铺满了光滑的卵石。
3. 3.The builders used packstones to create the walls of the castle.
   建筑师们用卵石建造了城堡的墙壁。