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，这个活梦，这个“来自泥灰岩鳄鱼”是如何进化而来？

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

沟底部泥灰岩很快就变成了粘稠泥浆，一块干涸土地不断。

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炸成碎片或撞到背部。

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

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