It is a kind of marl, of a brown or reddish color.

它是一种泥灰岩，呈棕色或微红色。

Now, how did this living nightmare, this " crocodile from the marl, " come to evolve?

现在，这个活生生的噩梦，这个“来自泥灰岩的鳄鱼”是如而来的？

The marl at the bottom of the trench is soon a sticky mud, and the one dry patch is continually being sniped.

沟底部的泥灰岩很快就变稠的泥浆，一块干涸的土地不断被狙击。

In the light sandy marl this does not take long, though many are blown to pieces or hit in the back as they scrape.

在浅色泥灰岩中，这不会花很长时间，尽管许多在刮擦时会被炸碎片或撞到背部。

There was clay or soft marl mixed with the chalk, and every here and there I saw the same footstep, both ascending and descending.

有土或软泥灰岩与粉笔混合在一起， 我到处都看到相同的脚步声， 既有上升也有下降。