英语语法分析

And the boundary of them has the same lithologic character: the ravinement surface of river course or exposure mudstone of flooding plain and root clay.

二者的界面是相同的，均为河道砂体底部的冲刷侵蚀面或者是暴露过泛滥平原泥岩、根土岩等。

It is condensed section with shells, downlap surface and ravinement surface that constitute the critical boundaries in dividing the system tracts of Matuo Formation.

含有介壳的凝缩段、下超面及沟蚀面是划分玛托组体系域的关键界面。